Table of Contents Climate Control Workbook Subject Page Introduction .7 Heating System.7 Basic Heating System Components .7 Heat Management .9 Intelligent Heat Management .10 Fuel Consumption.10 Exhaust Emissions.10 Power Output.10 Comfort .10 Component Protection.10 Air Conditioning System .11 Basic A/C System Components.11 The Refrigerant Cycle.12 A/C System Diagnosis.14 Refrigerant Pressure.14 Visual Inspection.15 A/C Quick Check .15 Service Information .16 Condenser Service .16 Evaporator Service .16 Expansion Valve Service.17 Compressor Service .18 Initial Print Date: 10/07 Revision Date: Table of Contents Subject Page Leak Testing the A/C System .19 Normal Operation Pressure Readings.20 Low Pressure Readings .21 High Pressure Readings.21 Combined High and Low Pressures .21 Safety Precautions .28 Typical Symptoms Complaint/Cause/Correction.47 Outlet Temperature Initially Cold then Warm.47 Outlet Temperature Not Cold at All.48 Outlet Temperature Cool but Not Cold.49 Low Cooling Performance with Icing atTEV .50 Not Cold with Loud Compressor Operation .51 Not Cold with Visible Icing Near Dryer .52 Not Cold with Compressor Freguent Cycling .53 Climate Control Systems.54 IHKS .54 IHKR .54 IHKA .54 FKA (E70).54 FKA (E66).54 E70 Dual Zone IHKA .55 E70 Four Zone IHKA with FKA .56 E66 Rear Air Conditioning FKA .57 E70 Third Row Heating/Ventilation .58 Table of Contents Subject Page IHKA Systems .59 Water-based Temperature Controlled IHKA .59 Air-based Temperature Controlled IHKA .60 Vent Temperature Stratification .61 The Y Factor .63 Climate Control Components.64 Climate Control Panel/Module (E90 IHKA) .64 Digital Motor Electronics (DME) Control Module.64 Junction Box (JB) .64 Roof Control Panel (FZD) .65 Car Access System (CAS) .65 Car Communication Computer (CCC).65 Central Information Display.65 Center Console Switch Cluster (SZM) .65 IHKA Inputs .68 Interior Temperature Sensor .70 AUC Sensor .70 Solar Sensor.71 Condensation Sensor.71 Outlet Temperature Sensor.73 Evaporator Temperature Sensor.74 Heater Core Temperature Sensors Left/Right .75 Ambient Outside Temperature .75 IHKA Outputs .81 Compressor Operation .81 Blower Motor/Final Stage.81 Table of Contents Subject Page Water Valves .82 Water Valve (Air Temperature Control) .82 Auxiliary Water Pumps.82 Electric Water Pumps .83 Map Thermostat.84 Auxiliary Fan Control (from 99 MY).84 Stepper Motors .85 Conventional Stepper Motors .85 “Smart” Stepper Motors .85 E65 Stepper Motors .86 E60 Stepper Motors .87 E9X Stepper Motors .88 EAB Stepper Motor .89 EFB Stepper Motor .89 E70 Stepper Motors .91 Replacement of a Stepper Motor .91 IHKA Functions and Features.98 E9XIHKA Functions .100 Temperature Control.100 Evaporator Control.101 Air Distribution Setting .101 Airflow Control .101 Front Stratification Adjustment Thumbwheel .101 Rear Stratification Adjustment Thumbwheel .101 Sunlight Adaptation (solar sensor) .102 MAX Cooling .102 Table of Contents Subject Page Residual Heat (REST).102 Switch-on Conditions: .102 Conditions for Switching Off: .102 Defrost Function .103 AUTO Function .103 Heated Rear Window .103 Defrosting Phase (1st heating period).103 Pulsing.103 2nd Heating Period.103 OFF .103 Air-recirculation Mode.103 Automatic Air-recirculation Control .104 Condensation Sensor Program.104 Convertible Mode (E93).105 Condition Based Service.106 Fresh Air/Recirculating Air Filters .106 Fresh Air Filtering .106 Recirculated Air Filtering .106 Climate Control Workbook 6 Climate Control Workbook Model: All Production: All ■BIICTWIS After completion of this module you will be able to: • Understand A/C refrigerant circuit operation. • Identify and locate refrigerant system components. • Understand the operation of the Climate Control Systems. • Identify the different components of the Climate Control Systems. Diagnose and service BMW Climate Control Systems. Introduction The purpose of the heating, ventilation and air conditioning system (HVAC) is to treat the air entering the passenger compartment in order to achieve and maintain a constantly comfortable environ¬ ment for the occupants. The modern automotive system that adds/removes heat, dehu- midifies, ventilates and filters the air entering the passenger com¬ partment is referred to as Climate Control. Climate Control describes a more complete and precise management of the basic HVAC system, where the climate of the vehicles is constantly var¬ ied and adjusted depending on the occupants desired and reguested settings. The Climate Control System must: • Adjust the temperature of the passenger compartment, depending on the reguirements of the driver / passenger and dictated by outside temperatures. • Circulate air through out the vehicle. • Remove moisture, assist in defogging of the windows and enhancing occupant comfort level. • Filter the air to remove dust, allergens. Climate Control can be divided into the following Sub-Systems: • Heater • Air Conditioning • Air Management (blower, filters, vents) • Computer Controls (inputs and outputs) Heating System The “heater” or heating system of a vehicle is typically dependent on the vehicles engine cooling system. To analyze one we must first discuss the other. The engine cooling system is essentially responsible for the extraction and dissipation of the excess heat that results from the internal combustion process and friction forces associated with the normal operation of an engine. Once the operating temperature has been reached the system dedicates most of its resources into controlling and maintaining this operation temperature. At the same time the surplus heat is diverted to the heater core inside of the vehicle where a blower motor fan is used to circulate heat through the passenger com¬ partment. Basic Heating System Components • Coolant • Radiator • Radiator cooling fan • Water pump (electric or mechanical) • Thermostat (conventional or Data-Map) • Coolant pipes and hoses • Auxiliary water pump (optional) • Coolant/water valve (optional) • Heater core • Blower motor/fan Climate Control Workbook 7 8 Climate Control Workbook Typical Cooling System Showing Heating System Components PASSENGER COMPARTMENT ENGINE TEMP SENSOR ENGINE COMPARTMENT RADIATOR OUTLET TEMPERATURE SENSOR ^ , ELECTRICALLY HEATED THERMOSTAT IHKA CONTROLLED WATER VALVE BLEED SCREW EXPANSION TANK \ HEAT EXCHANGER - THERMOSTAT TRANSMISSION HEAT EXCHANGER Heat Management The engine management DME (ECM) controls the coolant flow depending on the following conditions: • Low output when cooling reguirement is minimum and outside temperatures are low. • High output when maximum cooling is required and outside temperatures are high. The electric coolant pump may be completely switched off under certain conditions (to allow the coolant to heat up rapidly during the warm-up phase). However, this only occurs when no heating is required and the outside temperature is within the allowed range. The electric pump also operates differently from conventional pumps when controlling the engine temperature. Previously, only the currently present temperature could be controlled by the ther¬ mostat. The software in the engine control module now features a calculation model that can take into account the progression of the cylinder head temperature based on load. In addition to data-map control of the thermostat, the heat management system makes it possible to use various data maps for the purpose of controlling the coolant pump. For instance, the DME can adapt the engine tem¬ perature to match the current driving situation. This means that four different temperature ranges can be imple¬ mented: • 111 0 C(232°F) ECO mode • 105°C (221 °F) Normal mode • 95°C (203°F) High mode • 80°C (176°F) High + data-map thermostat mode If the engine management DME (ECM) selects ECO mode based on the current operating conditions, the system aims to bring about a higher cylinder head temperature of 111 °C. The engine is operated with relatively low fuel consumption in this temperature range as internal friction is reduced. An increase in temperature therefore favors lower fuel consumption in the low load range. In High and Data-map thermostat mode, the driver wishes to utilize the optimum power development of the engine. The cylinder head temperature is therefore reduced to 80°C. This results in improved volumetric efficiency, thus increasing engine torque. The DME (ECM) can then set an operating mode adapted to the particular driving situation. Consequently, it is possible to influence fuel consumption and power output by means of the cooling system. Index Explanation Index Explanation 1 Air-temperature data map 5 Chip 2 Load data map 6 Electric fan 3 Road-speed data map 7 Data-map thermostat 4 Coolant-temperature data map Climate Control Workbook 9 10 Climate Control Workbook Intelligent Heat Management The previous section explained the operating modes in which heat management was implemented. However, an electrically driven coolant pump makes even more options possible. For instance, it is now possible to warm up the engine without the coolant circulat¬ ing, or to allow the pump to continue running after the engine is switched off in order to facilitate heat dissipation. The advantages offered by this type of pump are listed below: Fuel Consumption • Faster warm-up as coolant is not circulated (stationary) • Increased compression ratio through greater cooling capacity at full load compared to the predecessor engine Exhaust Emissions • Faster engine warm-up due to drastically reduced pump speed and the resulting minimal volumetric flow of coolant • Reduced friction • Reduced fuel consumption • Reduced exhaust emissions Comfort • Optimum coolant volumetric flow. - Greater heater output when demanded. - Residual heat when engine is not running. Component Protection • Electric pump overrun achieves more effective heat dissipa¬ tion after switching off engine when hot coolant at the rate determined by the engine speed. • Only the circulated amount of coolant can be influenced by the mapped thermostat for temperature control purposes. • The system switches between the small and large circuit, i.e. the circuit flowing via the radiator. This consequently means that the cooling capacity is dependent on the engine speed. • If the heater core temperature exceeds safety parameters, the IHKA module will manipulate the thermostat settings to lower the overall heat in the system to protect the core from burst¬ ing. Power Output • Component cooling independent of engine speed • Demand-based coolant pump output • Avoidance of energy loss Air Conditioning System An air conditioning system does not produce cold air but rather it carries heat away from the vehicle interior to the outside. The closed system is filled with a refrigerant (R12 or R134a) which is circulated and provoked to change state from a liguid to a gas and back again. Basic A/C System Components • Refrigerant • Condenser • Condenser fan The air conditioning system operates in accordance with the refrig¬ erating principle. Circulating through this closed system, the refrig¬ erant is compressed, heated, expanded and cooled as it extracts heat and humidity from the air of the passenger compartment. E90 A/C System Components Compressor Expansion valve Hoses and pipes Receiver Dryer/collector • Evaporator • Compressor Control Device • Blower Fan Additional components of the A/C system include: • Compressor pulley (Clutch or Clutchless) • Pressure switch/sensor • Evaporator temperature sensor Climate Control Workbook 11 12 Climate Control Workbook The Refrigerant Cycle The refrigerant circuit is divided into a high pressure section (high side) and a low pressure section (low side). The high pressure side is comprised of the compressor, condenser, condenser fan, pres¬ sure sensor, receiver dryer and expansion valve. The low pressure side also involves the compressor and expansion valve along with the evaporator and blower fan.The expansion valve separates the high-pressure side of the system from the low-pressure side. Pressurized liquid refrigerant exits the receiver dryer and as it pass¬ es through the metered orifice of the expansion valve it decom¬ presses and boils. This change of state causes the refrigerant to absorb heat as it makes its way through the inside the evaporator. The amount of refrigerant released is controlled by the expansion valve based on evaporator temperature and pressure as well as the temperature of the air passing through the evaporator and proportional to the cool¬ ing demand. If too little refrigerant enters the evaporator, poor cool¬ ing results. If too much refrigerant enters, it might not completely boil away and liquid refrigerant might return to the compressor, causing damage to the system. Typical Expansion Valve ® Index Explanation Index Explanation 1 Diaphragm 9 Housing 2 Sending gas 10 From evaporator 3 To compressor A High pressure 4 Valve needle B Low pressure 5 From condenser C Sensing gas pressure 6 Spring Pfu Pressure in sensor line (sensor fill) 7 Ball Psa Evaporator pressure (low pressure) 8 To evaporator Pfe Control spring force The pressure and temperature are measured by passing the refrig¬ erant through the expansion valve at the outlet of the evaporator. The top section of the valve measures the temperature of the refrigerant intake and the refrigerant pressure acts on the underside of the diaphragm. The valve needle is pressed down against a spring to open the valve, allowing liguid refrigerant to flow into the evaporator. The refrigerant evaporates, pressure and temperature drop. The pressure and temperature of the gaseous refrigerant at the evaporator outlet are used to open and close the valve via a diaphragm. When the air temperature at the evaporator outlet drops, the sens¬ ing gas in the diaphragm chamber contracts, this moves the valve needle upward and reduces the refrigerant flow rate to the evapora¬ tor. The flow rate is increased again when the air temperature at the evaporator output rises. Increasing pressure at the evaporator outlet assists the valve closing action. Decreasing pressure assists the valve opening action. This control procedure runs continuously for as long as the air conditioning system is in operation. Heat is extracted from the cabin air as it is circulated by the blower fan through the evaporator outer surface area. This transfers heat from the cabin air to the vaporizing refrigerant inside, reiterating that an air conditioning system operates by removing heat instead of adding cold. An engine driven compressor extracts the, gaseous, low pressure refrigerant from the evaporator, compresses it and heats it. The now compressed and superheated gas is pumped through the condenser where it cools to a medium temperature, high pressure liguid as out side air is forced through the condenser fins via driving or the condenser cooling fan. The refrigerant now in a subcooled liguid state flows from the con¬ denser to a liguid reservoir (receiver dryer) where it is collected. Any moisture and impurities are removed by the desiccant in the receiv¬ er dryer. This high pressure liguid now flows back into the low pres¬ sure side of the system, where it is forced through the expansion valve metered orifice back into the evaporator on its way to com¬ plete the cycle once again. Climate Control Workbook 13 14 Climate Control Workbook A/C System Diagnosis Refrigerant Pressure Refrigerant pressure is directly proportional to its temperature so as the temperature goes up so does the pressure and vice versa. Refrigerant in the A/C system is provoked to change state from a liquid to a gas and back again. During every change of state heat is either absorbed or given away in the process. This thermody¬ namic property is put to use in the Low Side and in the High Side of all A/C systems. The low side pressure is a direct reading the evaporator tempera¬ ture and its heat exchanging capabilities. Low side pressures should average +/- 2bar. (28 to 32psi) that means that actual pres¬ sure of a variable displacement compressor/TEV system can be between 1 to 3bar. or (15 to 45psi) at any given time. The high side pressure is a direct reading of the condenser cool¬ ing efficiency. Although high side pressures may vary between 150 to 300psi. normally they should be about 2 to 2.5 times the ambient temperature. Depending on humidity, an outside temper¬ ature of 80°F should produce a pressure of 160 to 200psi on the High Side. When the high side pressure is way above normal it may indicate that the condenser auxiliary cooling fan is not cooling the refriger¬ ant sufficiently. Proper airflow across the condenser insures the efficiency of the entire system. The cooler the refrigerant leaving the condenser the lower its pressure; consequently the lower the temperature of the refrigerant entering the evaporator the more heat can be absorbed from the passenger compartment. Pressure gauges are indispensable when diagnosing an A/C sys¬ tem BUT they are incapable of measuring the quantity or for that matter the type of refrigerant in the system. The refrigerant capacity of an A/C system can be found on the A/C label under the hood and in the respective technical informa¬ tion relating the specific system. BAYERISCHE M0T0REN VERKE A3 MONCHEN, GERMANY — fSt\ __ FoUmcng* 590 ♦ 10# Nut R13*«(CfjCHir ACHTUNGI SthljndiUlHnjti KIl**an’.»g« ■tilst’i unt>r 0 e«fc» Ottnti liftMifti AUTOMOTIVE AIK CONDlT.CNEK CONFORMS TO SAE ^639 Chtro* 1.30 * 0.02 ONLY R13»«i*»i undif 'J®** r% * «4 m f E93 Under Hood Label Note: For more information on quantity and type of refrig¬ erant and refrigerant oil refer to the Operating Fluids Section (Group 64) on TIS. Visual Inspection It is important to understand the overall condition of the system. Some time between verifying the Customer Complaint and the A/C Efficiency Test, a Visual Inspection of the system should be per¬ formed. This Visual Inspection may cover, but is not limited too: • Compressor drive belt condition • Compressor drive pulley type and condition • Compressor engagement • Condenser fan operation. • Cooling system condition and operation • Heater valve operation • Blower fan operation • Refrigerant system integrity (a/c hoses, connections and fittings) • Electrical system malfunctions (Fuses/Relays) • IHKA settings and controls • Individual vehicle equipment options • Ambient temperature • Relative humidity • Customer system expectations E60 vent outlet temperature reading A/C Quick Check • Note ambient humidity • Note ambient temperature • Note refrigerant type (R-134a) • Close all windows and doors. • Engine Speed = 1500-2000 RPM. • Blower Volume = Medium Speed • Temperature Wheel = “Max Cold” • “Snowflake” Button = A/C On • Test conditions > 3 minutes • Center vent discharge = 20°F less than the ambient temperature. Climate Control Workbook 15 oix #»' 16 Climate Control Workbook Service Information Condenser Service The procedure in the condenser is divided into three operations. In the first stage, the hot gaseous refrigerant at a temperature of about 60-120°C coming from the compressor at a pressure of 10 to 25 bar gives off its superheat to the outside air. The actual con¬ densation takes place in the second phase where the refrigerant has lost so much energy that it becomes liguid. In the third phase, further energy is taken from the now liguid refrigerant. This state is referred to as refrigerant sub-cooling. This phase also makes sure that no gas bubbles can form on the refrigerant’s way to the expan¬ sion valve. The sub-cooling takes more heat away from the refriger¬ ant than is necessary for actual condensation. The sub-cooled refrigerant in the evaporator can absorb a larger guantity of heat and thus increase the refrigerating capacity of the system. The aux¬ iliary fan arranged directly before the condenser ensures an effec¬ tive supply of cooling air. The refrigerant remains in the condenser at a high pressure of approx. 10-25 bar. Approx. 80-90% of the condenser is used in the actual condensation process where a temperature drop of 30 to 40°C occurs. The following points must be observed when working on the condenser: • The distance between the condenser and vehicle radiator must be as large as possible. • The condenser fins must not be bent or dirty. • Ensure the auxiliary fan is operating correctly. • A soiled condenser results in poor condensation and unnecessarily high operating pressures. Note: The sub-cooling of the refrigerant in the condenser enhances the efficiency of the air conditioning sys¬ tem. Evaporator Service The evaporator functions as a heat exchanger in that thermal ener¬ gy is taken externally from the air and given off internally to the refrigerant. The most important factor is the energy absorption by the refrigerant during the transition from the liguid to the gaseous state.This transition reguires a great deal of energy in the form of heat which is taken from the air blown through the system of fins. The refrigerant cools down greatly while the injection procedure ensures the pressure drops from 10-20 bar. to about 2 bar. The refrigerant is evaporated at low pressure by the heat delivered from the passenger compartment with the use of a blower fan. The following points must be observed when working on the evaporator: • The evaporator fins must not be dirty or bent. This would result in the growth of bacteria and odor. • The evaporator fins must not ice up. If the evaporator does ice up, the fault will be in the area of the evaporator temperature sensor. This situation may result in compressor damage. • The micro filter change intervals must be maintained to insure adeguate airflow. • The condensation water drain must not be clogged and water must drain off freely. • The evaporator temperature sensor must be installed correctly. Note: To treat bacteria and odor complaints, a special cleaning and treatment procedures must be followed. SI 64 04 03 “A/C System Musty Odor” can be found in TIS. Expansion Valve Service A block-valve design of expansion valve is used on current BMW A/C systems. The refrigerant enters at the upper right inlet. At the left of the valve there is a capillary tube filled with an inert gas that senses the temperature of the air coming into the housing from the plenum. When the air temperature in the plenum rises, the pressure in the capillary tube increases. This pushes down on a diaphragm and pushrod assembly, which increases the size of the orifice opening, allowing more refrigerant into the evaporator and providing more cooling. When plenum temperature falls, the pressure in the capillary tube falls. The spring pushes up on the pushrod, making the orifice opening smaller; less refrigerant is allowed into the evaporator, allowing less cooling. Refrigerant from the outlet of the evaporator passes through the bottom left opening of the block valve. When the pressure at the evaporator outlet is high, this increases the pressure needed by the capillary tube to open the valve. Less refrigerant is provided to the evaporator (to prevent the evaporator from being flooded). When pressure at the outlet end of the evaporator is lower, less pressure is exerted on the bottom of the diaphragm. The diaphragm pushes down on the pushrod, allowing more refrigerant into the evaporator. The following points must be observed when working on the expansion valve: • Very little refrigerant flow through the evaporator will result in poor AC output. • Too much refrigerant flow will flood the evaporator and cause possible compressor damage. • The setting of the expansion valve must not be adjusted or varied (except for instructions in the Service Information). • The expansion valve must not be repaired. • Seals must be replaced every time the pipes and hoses are released. • It is imperative that an A/C system being serviced be evacuat¬ ed for a minimum of 30 minutes or more in order to remove any possible moisture trapped within. Note: If moisture gets into this system, it may freeze and clog the expansion valve. The A/C system may oper¬ ate normally for a while, then stop cooling. Then, as system temperature increases, the ice melts. The system works again for a while, until moisture freeze- up causes it to stop again. Climate Control Workbook 17 18 Climate Control Workbook Compressor Service The function of the compressor is to pump the refrigerant along the system. As the gaseous refrigerant exits the evaporator, it is pulled into the compressor by suction where it is compressed and super¬ heater and then pumped along to the condenser. Liquid refrigerant in the compressor causes noise complaints and internal damage. There are currently three methods of compressor control and two types of compressors depending on the vehicle or equipment option. (See Compressor Operation) Typical Compressor service points to remember: • When troubleshooting a noisy compressor complaint, make sure the noise is present only when the clutch is engaged. • If it is present when the clutch is not engaged, remove the compressor drive belt and check again. • If the noise continues, it is not related to the compressor. • If removing the drive belt reduces or eliminates the noise, check the torque of the compressor and bracket mounting bolts. • Check the belt tension and condition, and tensioner pullies which can produce rattling noises that would sound like a defective compressor. • A loose/slipping belt can cause noise. • A belt that is too tight can damage the clutch/pulley bearings. • If the compressor is noisy with the compressor clutch engaged, make sure the system is charged with the correct amount of refrigerant. • An over-charged system can cause compressor noise. • If the A/C system is overcharged with refrigerant, the liquid entering the compressor can damage it. • When troubleshooting a noisy compressor complaint, recover the refrigerant and recharge the system with the correct amount. • A failed compressor must be returned with the inlet and outlet ports sealed using the plastic caps from the replacement compressor. Otherwise the “failed” compressor will be dam¬ aged by moisture, and it will be impossible for Warranty to ana¬ lyze it. Compressors with plastic pullies: • Avoid impact on the plastic pulley (through tools, contact with base) • Send back damaged compressors only in original packaging. Note: It is important to perform the following running-in procedure when operating a new compressor for the first time. • Switch off air conditioning system • Set all air outlet nozzles on the instrument panel to "OFF" • Start engine and allow idle speed to stabilize • Set blower capacity to min. 75% of the maximum blower capacity • Switch on air conditioning and allow to run for at least 2 min¬ utes at idle speed. Risk of damage at higher speed! (Refer to BMW Diagnostic Equipment Service Functions for more detailed instructions) Note: When replacing a compressor you must follow the instructions on refilling the refrigerant oil. For details on compressor replacement and oil capacities are found in the Operating Fluids Information in TIS. Leak Testing the A/C System Always be aware of the safety measures associated with handling refrigerant as far as wearing eye protection, gloves and respiratory eguipment. (Refer to Safety Section) If the refrigerant leak was not identified during the evacuation, the system must be filled before it can be tested for leaks with either dye or the electronic leak detection device. Typical Electronic Leak Detector Using a leak detector like this takes experience and practice. Many times an oily black dust collects on or around leaking component. This evidence of escaping oil and refrigerant and is a very good place to start. To check for a leak with dye, the dye has to be added to the sys¬ tem and then monitored using an ultraviolet lamp and special safe¬ ty glasses. When the ultraviolet beam of light shines on the sus¬ pected component/area, it reflects a yellow glow as evidence of the refrigerant leak. Typical Fluorescent Dye Leak Detector Kit These are some helpful leak testing tips to keep in mind: • It is better to check the Low Side for leaks with the A/C sys¬ tem off. • The High Side is best checked for leaks with the A/C system on. • Refrigerant is heavier than air. Therefore you must always test below the suspected lines, connections and components. • Solvent fumes, wind and cooling fans may throw off your diag¬ nosis. • Remember that refrigerant dye stains and a leak inside the vehicle like an evaporator can damage the interior. • Evaporator leaks are best diagnosed with an electronic leak detector at the outlet vents and at the condensation drain with the system off. Note: Refer to SI B 04 14 04 “A/C Leak Detection Kit” R- 134a A/C dye leak tester has been approved for use on BMW Group vehicles. Climate Control Workbook 19 20 Climate Control Workbook Normal Operation Pressure Readings Index Explanation 1 Low pressure - normal 1 to 2 bar (1 5 to 30psi) 2 High pressure - normal 10 tol 5 bar (1 50 to 225psi) These pressures will vary depending on outside temperature and humidity. Readings that differ from above are not considered cor¬ rect and may indicate a problem. Proper interpretation of these reading will allow you to make an accurate diagnosis of the system. Although the typical outlet temperature for a properly operating system should be 20° lower than the current ambient temperature, outlet temperature may range between 40 to 68°F at any given time depending on outside temperature and humidity. Note: Refer to S.I.B. # 641392 (3646) for nominal air conditioning system pressures R12/R134a. Relative Humidity (%) Outside Air Temp ( & F) R-12 Discharge Tsmp(’F) R-12 Low Pressure ipsi) R-12 High Pressure (psi) R-134S Discharge Temp (F) R-134a Low Press ure (psi) R-134a High Pressure (psi) 20 70 44 24 143 44 9 69 80 44 31 192 44 24 85 90 50 45 232 47 40 136 100 59 47 270 53 50 231 110 66 57 320 64 58 306 30 70 44 23 154 44 10 80 80 44 35 203 44 28 110 90 54 47 239 48 42 168 1 100 63 50 283 59 54 253 110 74 60 334 69 62 328 40 70 44 34 170 45 12 93 30 50 40 216 50 32 149 90 58 48 146 56 45 212 100 67 53 291 64 57 264 110 77 63 350 74 67 348 ! 50 70 4B 37 178 45 14 102 so 55 43 223 51 36 164 90 61 50 252 59 54 229 100 71 58 312 70 67 229 110 84 66 365 80 76 366 60 70 47 40 167 45 IS 133 80 55 49 230 53 39 191 90 64 54 266 62 57 249 100 75 60 318 72 72 310 110 86 68 383 63 80 384 70 70 47 41 228 46 19 168 80 56 50 257 56 42 215 90 66 56 276 67 61 260 100 78 63 333 77 75 321 110 91 72 402 87 87 390 80 70 47 43 £47 46 21 176 80 57 53 268 57 47 216 90 69 62 287 69 67 267 100 82 70 340 78 80 331 110 95 76 436 90 69 405 90 70 48 44 258 46 33 183 60 60 55 286 59 54 223 90 72 63 307 71 69 274 100 85 72 350 64 S4 345 110 101 80 463 67 94 424 Low Pressure Readings • A Low pressure reading in both High and Low gauges usually indicates Low refrigerant charge. • Very low pressures on both sides, with even a vacuum reading on the low side will typically indicate: - A restriction on the receiver dryer (with auxiliary fan on) - Expansion valve restricted or not opening (with auxiliary fan on) - The low pressure on high side here indicates a restriction because as the refrigerant is trapped in the condenser (not circulating) the auxiliary fan continues to cool it and thus lowers its pressure. High Pressure Readings • A High pressure reading on the Low side typically indicates overcharging • A high pressure on the Low side may indicate an open expan¬ sion valve. • A high pressure reading on both high and Low side typically would indicate - Overcharging - Condenser cooling fan not working - Oil saturation of the system (condenser) - Expansion Valve Stuck Open (not closing) Combined High and Low Pressures • Low pressure high and high pressure low normally indicates: - Reduced Compressor output - Compressor belt slipping - Compressor clutch defective - Compressor control defective - Compressor control failure • Low pressure low and high pressure normal to high. - Restriction in dryer (auxiliary fan NOT on) Note: These examples are just for sole purpose of the explanation of the system operation. In service, sys¬ tem pressures may behave differently based on the conditions at the time of testing. Climate Control Workbook 21 22 Climate Control Workbook Typical Air Conditioning System 4 } Classroom Exercise 1 - Review Questions 1. Which of these materials is used to absorb moisture? Select the best possible answer. a) Refrigerant c) Lubricant b) Desiccant d) Catalyst 2. What happens to the refrigerant in the evaporator? Select the best possible answer. a) Absorbs heat c) Expands b) Boils d) All of the above. 3. Which two major A/C components are combined in some current BMW A/C System? Select the best possible answer. a) Evaporator / Expansion Valve c) Dryer / Condenser b) Condenser / TEV d) All of the above. 4. What does water on the carpet of the passenger compart¬ ment indicate? Select the best possible answer. a) Expansion valve open c) Leaking Evaporator b) Leak in Condensation Hose d) Both C and B Climate 5. What does a “musty odor” from the A/C system vents indicate? Select the best possible answer. a) Mold in the A/C System c) Leak in the Condenser b) Stuck open Expansion Valve d) Leaking Heater Core 6. Fill in the following legend pertaining to the diagram in the opposite page. Workbook 23 24 Climate Control Workbook | Classroom Exercise 2 - Review Questions 1. Why do current vehicles use Map controlled thermostats? Select the best possible answer. a) Thermal Efficiency c) Tailpipe Emissions b) Fuel Economy d) All of the above 2. Why is pulling a continuos vacuum on an empty A/C System imperative to it’s efficiency? Select the best possible answer. a) To purge all air c) To drain all the oil b) To extract all the Refrigerant d) To extract moisture 3. What are the two main functions of the evaporator? Select the best possible answer. a) Dry the air c) Absorb heat b) Release heat d) Both A and C 4. What is the minimum amount of time we should pull a vacuum on a system before charging? Select the best possible answer. a) 1 hour b) 30 sec. c) 15 minutes d) 30 minutes Match the heating system component with it‘s air condi¬ tioning counterpart. Heating System A/C System Radiator Refrigerant Radiator fan Evaporator Water pump Condenser Map Thermostat Auxiliary fan Pipes and hoses Blower fan Expansion tank Compressor Coolant Expansion valve Coolant/water valve Lines and Hoses Heater core Receiver dryer Blower fan Compressor control (Valve/Clutch) Workshop Exercise - A/C Efficiency Test Satisfy the following conditions before performing an A/C efficiency test. • Connect the BMW Diagnostic Equipment and check for faults (no faults in the fault memory). • Use a thermometer with separate gauge. • Perform the test in a suitable work bay with an ambient temperature between 20°C and 30°C (68° F and 86° F). 1) Connect BMW Diagnostic Equipment to the vehicle and 4) Perform the A/C efficiency test and document below. display evaporator temperature. t a/ ~ . ....... • Turn on A/C compressor at a vehicle interior tempera¬ ture of 50°C (122°F). 2) Position a (pocket) thermometer with a separate gauge about • After 3-4 minutes, the evaporator sensor temperature 5cm (2in) below the roof liner at the height of the B-pillar. must be 15°C (59°F) or below. Position the gauge facing outside of vehicle interior. 3) Heat up vehicle interior: • A/C button is not activated during heating up. • Close all windows and doors. • Set recirculated air mode. • Select air distribution mode for footwell and defrosting. • Maximum temperature setting. • Maximum fan stage. • Run engine at @ 2000 rpm until operating temperature is reached, then idle speed. 5) If this temperature is not reached: • Recycle the refrigerant from the A/C system. • Measure amount of refrigerant collected. 6) If the collected refrigerant quantity does not correspond to specified fill quantity: • Recharge with the correct amount of refrigerant and repeat the efficiency test. 7) If fill quantity is correct: • Continue troubleshooting by refrigerant pressure readings. Climate Control Workbook 25 26 Climate Control Workbook Workshop Exercise - Intro/Demo Using the A/C Sen/ice Equipment and BMW Diagnostic Equipment demonstrate the following. 1. Perform a visual inspection on the vehicle and list any find¬ ings below. 4. Perform the cooling system bleeding procedure and list the steps below. 2. Pinpoint the location of all crusial components of the A/C System and check them off the list below. Expansion Valve Compressor Compressor Clutch Condenser Refrigerant Pressure Switch Low Side Service Port IHKA Single Zone Condenser W/integrated Dryer Receiver Dryer (stand alone) Water Valve Clutchless Pulley Auxiliary Water Pump High Side Service Port IHKA Dual Zone 5. Perform the compressor run in procedure on your test vehi¬ cle and list the steps below. 3. Proceed to install the A/C Service equipment and demon¬ strate the proper procedure to Recycle refrigerant Evacuate and Recharge the A/C System. 28 Climate Control Workbook Safety Precautions The following safety precautions should be observed when work¬ ing on an automotive refrigeration system: • Always wear eye protection and gloves while handling refriger¬ ant or servicing an air conditioning system. • Avoid breathing R-134a vapor or mist; exposure may irritate eyes, nose, throat, and lungs. • If refrigerant or compressor oil con¬ tacts the skin or eyes, rinse the affect¬ ed area with warm water, administer first aid immediately, and consult a doctor. • Use only, approved service eguipment to discharge A/C systems. • If an accidental discharge occurs, ven¬ tilate the work area. • Store refrigerant service eguipment and bulk supply contain¬ ers in a cool, dry location away from direct sunlight and other heat sources (<113° F, (45° C). • Do not expose refrigerant to an open flame, since burning refrigerant can produce poisonous gas. This includes open flames (such as in a propane leak detector), portable heaters, and lit cigarettes. • Do not pressure-test service eguipment or vehicle A/C sys¬ tems with an air/R-134a mixture. Some mixtures of air and R- 134a are combustible at elevated pressures. The use of com¬ pressed air for leak detection in an R-134a system could result in a fire or explosion. • Never weld or steam-clean any part of the air conditioning sys¬ tem. Heating the refrigerant in a closed system could cause an explosion, due to the increased pressure. • Always consider R-12 or R-134a to be under high pressure, whether in the automobile refrigeration system, service eguip¬ ment, or refrigerant storage containers. • R-134a should only be handled by competent, informed per¬ sonnel using approved procedures and equipment. Failure to do so may result in serious injury and/or substantial equipment or vehicle damage. • Removal of R-134a must be carried out using R-134a equip¬ ment that meets the requirements of SAE J2210. • If accidental discharge occurs, ventilate the work area before resuming service. • Exposure to high concentrations of refrigerant vapor can induce anesthetic effects such as weakness, dizziness, and nausea. • Do not discharge refrigerant into the atmosphere; contain it. • R134a is heavier than air; if discharged into the atmosphere, it can replace the air, causing suffocation. • If R-12 is discharged into the air it damages the environment. Note: Refer to repair instructions of group 64 for safety pre¬ cautions when handling refrigerant oil (for refrigerant R 134a) Workshop Exercise 1 - A/C System Diagnosis Using an instructor assigned vehicle, perform an A/C Quick Check on vehicle. Proceed to Verify Customer Complaint with diagnosis based on complaint listed below. Complete worksheet using proper format regarding, “Complaint/Cause and Correction”. Vehicle: Chassis #: Production Date: Complaint: AIR CONDITIONING INOPERATIVE Cause: Correction: Climate Control Workbook 29 30 Climate Control Workbook Workshop Exercise 1 - A/C System Diagnosis Turn vehicle on and set IHKA to max cool, allow system to stabilize. Check cabin/vent temperature and verify proper system per¬ formance based on ambient temperature and humidity. What are the cabin and vent temperature readings and do they verify the customer complaint? Turn off the engine and perform a visual inspection of controls, settings, belts, hoses and fittings looking for anything that may cause the customer complaint. Hook-up the A/C service station or manifold gauges, then start the engine and set IHKA to max cool, allow system to stabilize while monitoring manifold gauges. Record the readings on the gauges provided below. What should the correct pressures and vent temperatures be at the current outside temperatures and humidity? Compare these to the normal gauge readings. What do all these test result indicate? What is your suggested plan of action to diagnose the problem? LOW Side _ psi. HIGH Side _ psi. Vent F Ambient _ F Workshop Exercise 1 - A/C System Diagnosis Turn vehicle on and set IHKA to max cool, allow system to stabilize. Check cabin/vent temperature and verify proper system per¬ formance based on ambient temperature and humidity. Connect the BMW diagnostic equipment, perform Short Test What conclusions did you arrive to from following the test plan and list any Fault codes below. in the Symptom’s Menu. Are any of the recovered Fault Codes related to this problem? If you chose your own Test Plan, List your actions below. Is there a symptom in the Symptoms Menu that applies to our Where do you think the problem is? customer’s complaint? _ If yes, follow the Test Plan to completion and list the main steps below. Based on instructor evaluation: Return this vehicle to the condition you found it and move on to the next exercise or correct the problem and retest. Climate Control Workbook 31 Workshop Exercise 2 - A/C System Diagnosis Using an instructor assigned vehicle, perform an A/C Quick Check on vehicle. Proceed to Verify Customer Complaint with diagnosis based on complaint listed below. Complete worksheet using proper format regarding, “Complaint/Cause and Correction” Vehicle: Chassis #: Production Date: Complaint: AIR CONDITIONING “COOL BUT NOT REALLY COLD” Cause: Correction: Climate Control Workbook 33 34 Climate Control Workbook Workshop Exercise 2 - A/C System Diagnosis Using an instructor assigned vehicle perform the A/C Quick Check. With the engine off perform a preliminary visual inspection. Connect the A/C service station or manifold gauge, run the engine and A/C on MAX and record pressure readings below. Analyze the system and record pressure readings ,vent and out¬ side temperature. Following the A/C service station’s instructions perform the refrigerant recycle procedure. Why is it important to note the amount, if any of refrigerant that is recovered at this stage? Perform a complete evacuation of the system, observing that both gauges (high and low) register a steady and continuous vacuum reading for at least _ minutes. Why is it important to note the amount, if any of refrigerant OIL that is recovered at this stage? LOW Side _ psi. HIGH Side _ psi. Vent - F Ambient - F Why is it necessary to continue pulling a vacuum on the system even after it was fully evacuated and is now empty? Compare these to the normal gauge readings. What may all these readings indicate? _ When would a longer evacuation time be necessary? According to these readings what should be done next? _ Workshop Exercise 2 - A/C System Diagnosis Answer the following questions based on what you know up to now. Make sure the system holds vacuum for at least 5 minutes. If the refrigerant leak is large enough, it may be detected during Why is it imperative that the system hold vacuum for at least 5 min- the visual inspection. utes? What are we looking for as visual evidence that a component is possibly leaking? If the vacuum holds, can the system still be leaking? .... . . ., , ...... ...... ’ y a What is the procedure necessary to pinpoint a refrigerant leak that _ was not detected by visual inspection, the vacuum hold test or the electronic leak detector? If the vacuum does not hold, what is the necessary course of _ action? _ What pre-condition is best for detecting a suspected refrigerant leak in the liquid line of an A/C system? What tools can we use to pinpoint this refrigerant leak.? Climate Control Workbook 35 36 Climate Control Workbook Workshop Exercise 2 - A/C System Diagnosis What pre-condition is best for detecting a suspected refrigerant leak in the Low side of an A/C system? What tool is preferred when diagnosing an evaporator for refrigerant leaks and Why? What characteristic of refrigerant we must keep in mind when diag¬ nosing a refrigerant leak with an electronic leak tester? Using the appropriate leak detection method pinpoint the refrig¬ erant leak and state your findings below. What procedure has been approved by BMW to TEST empty evap¬ orators with out removing them from the vehicles? Based on instructor evaluation: Return this vehicle to the condition you found it and move on to the next exercise/vehicle or continue this exercise by: 1. Follow the appropriate procedure to pinpoint the refrigerant leak. 2. Proceed to recharge the refrigerant system properly. 3. Re- test the system for leaks. 4. Evaluate system performance to make sure it is back to original working order. 38 Climate Control Workbook Workshop Exercise 3 - A/C System Diagnosis Using an instructor assigned vehicle, perform an A/C Quick Check on vehicle. Proceed to Verify Customer Complaint with diagnosis based on complaint listed below. Complete worksheet using proper format regarding, “Complaint/ Cause and Correction” Vehicle: Chassis #: Production Date: Complaint: “AIR CONDITIONING NOT COLD ENOUGH” (POOR PERFORMANCE) Cause: Correction: Workshop Exercise 3 - A/C System Diagnosis Using an instructor assigned vehicle perform the A/C Quick Check and a preliminary visual inspection - Connect the A/C service station or manifold gauge, run the engine and A/C on MAX to stabilize the system pressures. Check the vent temperatures and refrigerant pressures and record them below. Vent _ F Ambient _F LOW Side _ psi. HIGH Side _ psi. Fill in the blanks. Following the A/C service station’s instructions: Perform the procedure to _ the refrigerant. How much refrigerant was in the system? How much refrigerant does the system specify? What is the difference between the specified refrigerant amount and the refrigerant recovered? Compare these to the normal gauge readings. What may all these readings indicate? - _ What did this test confirm? Based on observations, describe what is happening in the system. _ - Evacuate the system and note the amount of recovered. - Why is this last step important? What is the recommended next step in this diagnosis? Climate Control Workbook 39 40 Climate Control Workbook Workshop Exercise 3 - A/C System Diagnosis How much oil should you add to this system? Proceed to recharge the system with the correct amount of refrigerant. Based on the previous test results proceed to recharge the sys- tern properly. Evaluate system performance to make sure it is back to original How much refrigerant does the system call for? working order. Based on instructor evaluation: Return this vehicle to the condition you found it and move on to the next exercise/vehicle or continue to next step. 42 Climate Control Workbook Workshop Exercise4 - A/C System Diagnosis Using an instructor assigned vehicle, perform an A/C Quick Check on vehicle. Proceed to Verify Customer Complaint with diagnosis based on complaint listed below. Complete worksheet using proper format regarding, “Complaint/ Cause and Correction” Vehicle: Chassis #: Production Date: Complaint: “POOR PERFORMANCE AFTER A SHORT DRIVE” Cause: Correction: Workshop Exercise 4 - A/C System Diagnosis “Poor A/C performance after a short drive” Using an instructor assigned vehicle install A/C Manifold Gauges and BMW Diagnostic Equipment. Vent Temp. _ F Interior Temp. _ F Ambient Temp. _ F Engine Temp _ F CAUTION!!! ENGINE MA Y RUN HOT III Select the symptoms path on the BMW Diagnostic Equipment. Is there a symptom listed that applies to this customer complaint? If “YES” follow Symptom test plan and list findings below. Analyze the system and record pressure, temperature readings. What may these readings indicate? _ If “NO” what course of action may all these readings indicate in other to correct the problem? Perform a short test on the vehicle. List any faults related to the Customer Complaint. _ Correct the problem, retest if necessary then restore the vehicle to proper operating condition. Climate Control Workbook 43 44 Climate Control Workbook Workshop Exercise 5 - A/C System Diagnosis Using an instructor assigned vehicle, install A/C Manifold Gauges and BMW Diagnostic Equipment. Set the A/C to MAX cooling, allow the system to stabilize and verify the proper refrigerant pressures. STOP THE ENGINE Disconnect the cooling/condenser fan harness connector. Restart the engine and set the A/C to MAX. Pay close attention to engine temperature as you observe what happens and explain below. CAUTION!!! DO NOT OVERHEAT THE ENGINE HI! Shut down the engine, connect the fan and answer the follow¬ ing questions. What happened to the Low Side pressure? Analyze the system and record pressure, temperature readings below. LOW Side _ psi. Vent _ F Interior _ F HIGH Side _ psi. Ambient _F Engine _F How high did the High Side gauge go? Why do you think this occurred? Why did the High Side eventually come down? At what pressure did the High Side go back up? Why do you think this occurred? Classroom Exercise - A/C Gauge Reading Diagnosis. A/C cold initially but then turning warm again. Outlet temperature changes constantly between cold and warm. Low Side, unsteady low to vacuum readings, High Side, high to very high unsteady readings with Icing on expansion valve. What may the pressure readings above indicate? Check the best possible answer. Defective evaporator Inoperative Overcharged temp, sensor auxiliary fan system Based on the previous readings, what is the recommended next step in this diagnosis? Check the best possible answer. If a diagnostic check of IHKA inputs and outputs reveals no faults or problems what could the problem be? Based on the previous statements and clues, which solution do you think may correct this vehicle’s A/C problem? Check the best possible answer. • Recycle the refrigerant • Recycle the refrigerant • Replace the Condenser • Replace the Dryer • Add the correct oil charge • Evacuate the system • Recharge the system to • Add the correct oil charge specifications. • Recharge the system to specs Check IHKA inputs/outputs Recycle the refrig¬ erant and recharge correctly Check the auxiliary fan circuit • Recycle the refrigerant • Replace the Evaporator Sensor • Recharge to the correct amount • Add the correct oil charge Climate Control Workbook 45 • Recycle the refrigerant • Flush the system • Evacuate the system • Recharge the system • Add the correct oil charge Typical Symptoms Complaint/Cause/Correction Outlet Temperature Initially Cold then Warm 1 = Low pressure - normal to too low 2 = High pressure - normal to too high Symptoms Possible faults Repair • Outlet temperature is initially cold but then warm. • Evaporator/expansion valve partly ices up and then thaws again. • High pressure increases, low pres¬ sure drops to vacuum range. • Evaporator ices up before the com¬ pressor is switched off. • Slow compressor switching cycles. Moisture in refrigerant circuit. Recycle and Evacuate the system, replace the dryer and recharge. Temperature sensor for evaporator defective. Check evaporator temperature sensor and replace if necessary. Faulty pressure sensor or signal. Climate Control Workbook 47 48 Climate Control Workbook Outlet Temperature Not Cold at All 1 = Low pressure - too low 2 = High pressure - normal to too low Symptoms Possible faults Repair • Outlet temperature not cold enough "only a little cool but not really cold". Low refrigerant refrigerant in the system. Evacuate system, compare amount of refrigerant removed to reguired system capacity. Check for leaks, correct and recycle and recharge refrigerant to specific level. System leaks. Check for leaks and repair them, replace the component in guestion. Recycle, recharge the system to specifications and re-check. Failed expansion valve. Replace expansion valve and dryer, recycle, evacuate and recharge the refrigerant to specifications and leak test. Defective compressor. Replace the compressor, receiver dryer, evacuate, recharge to specifica¬ tions and leak test. Partial blockage of the receiver dryer. Recycle refrigerant, replace the dryer, evacuate the system, recharge to specification and leak test. Outlet Temperature Cool but Not Cold 1 = Low pressure - too high 2 = High pressure - too high Symptoms Possible faults Repair • Outlet tempera¬ ture cool but not cold. • Low side pipes hot to the touch. Air in the system. Leak test, replace dryer, evacuate, recharge to specifications and retest for leaks. Too much refrigerant in the system. Recycle the refrigerant, evacuate the system and recharge to specifications. Condenser blockage/dirty fins. Check condenser fins for debris or damage and correct. Condenser fan is not cooling. Check operation of condenser fan (fuse, relay, wiring, motor, stiff movement) and correct. Expansion valve does not close. Check installation and operation of temperature sensor, then replace expansion valve and dryer, Recycle, recharge and leak test. Climate Control Workbook 49 50 Climate Control Workbook Low Cooling Performance with Icing atTEV 15psi. To Vacuum Note: Check valve for obstructions such as dryer granulate, or metal chips from the compressor. If found, flush the entire system, blow out with air and replace any sus¬ pected component. 80psi. 1 = Low pressure - too low 2 = High pressure - too low Symptoms Possible faults Repair • Outlet temperature not cold enough "only a little cool and not really cold". • Low pressure may drop into vacuum range. • Visible icing on refrigerant lines from/to dryer. Moisture in the system. Leak test, recycle the refrigerant, replace dryer, evacuate, recharge and retest for leaks. Expansion valve blocked/does not open. Check installation and operation of temperature sensor. Isolate blockage. Recycle refrigerant, replace expansion valve and or receiver dryer. Evacuate, recharge to specifications and leak test. Filter dryer clogged, acts as throttle, refriger¬ ant expands in line before expansion valve. Not Cold with Loud Compressor Operation 44psi. Note: If metal chips are found, flush clean the entire system, replace the dryer, expansion valve and or any contaminated components, recharge and re-test. 1 = Low pressure - too high 2 = High pressure - too low lOOpsi. Symptoms Possible faults Repair • Outlet temperature insufficiently cold "not cold enough". • Compressor is loud. • Reduced compressor output. Compressor drive belt slipping. Check for correct tension of drive belt and replace belt if necessary. Magnetic clutch of compressor defective or incorrectly set air gap/clearance. Check operation of magnetic clutch, tempera¬ ture/pressure switches, wiring, fuse / relay, con¬ trol unit), adjust air gap if necessary. Compressor may be mechanically defective. Replace compressor, charge the system to specifications and check for proper operation. Climate Control Workbook 51 52 Climate Control Workbook Not Cold with Visible Icing Near Dryer 1 = Low pressure -too low 2 = High pressure - normal to high Symptoms Possible faults Repair • Poor or no cooling performance. • Visible condensation or icing on lines or on component. Blockage on high pressure side, generally in dryer. Isolate the blockage, recycle the refrigerant. Locate and repair blockage, replace the dryer, recharge to specifications, check for leaks and verify systems operation. Not Cold with Compressor Frequent Cycling Symptoms Possible faults Repair • Outlet temperature is not cold enough ("only a little cool but not cold enough"). • Frequent compressor switch-on cycles (short operation and short cut-out times). Temperature sensor for evaporator is defective switches incorrectly. Check evaporator temperature sensor. Verify electrical connection and replace if necessary. Climate Control Workbook 53 54 Climate Control Workbook Climate Control Systems There are a few different types of BMW climate control systems. Most of the current US vehicles are equipped with fully automatic climate control systems (IHKA). Each climate control system has different features and functions depending upon the vehicle appli¬ cation. IHKS Translated from German, the acronym means “Integrated Heating and Air Conditioning Control. This system does not regulate the interior temperature of the passenger compartment automatically. IHKS is single zone system, controlled directly by the driver to achieve the desired level of comfort and was installed on the E36/5(318ti), E36/7(Z3) and the E52 Z8 as standard equipment. IHKR The IHKR system is a “semi-automatic” climate control system. Interior air temperature is controlled automatically, but air distribu¬ tion and blower speed are controlled from the control panel by the driver. IHKR was used on the some early vehicles such as the E34 and E36 (up to 95). The most recent use of the IHKR system was on the E39 525, E53 X5 3.0, E46 325 and the E85 Z4 as stan¬ dard equipment (IHKA was available as an option). IHKR is also a single zone system, with only one temperature control for the entire passenger cabin. IHKA This is a fully automatic climate control system. Air distribution, blower speed and temperature regulation are controlled automati¬ cally. The system is designed to maintain the driver desired tem¬ perature setting automatically by monitoring interior temperature. The IHKA system is a dual zone system, with 2 temperature con¬ trols with some exceptions (the E46, E85 and E83 X3 with basic single zone IHKA). IHKA was first installed on 7 and 8 series vehi¬ cles. The system was added to the 3 series (E36, E46), then to the 5 series E39, E53 and it is currently available on all US mod¬ els. FKA(E70) This is a rear climate control system that is available currently on the E70 X5. By combining IHKA with FKA the system is consid¬ ered to be a true 4 zone system. Every passenger has the option to change the temperature of his sitting area independently with respect to the other occupants. FKA (E66) This is a Rear Compartment Air Conditioning system (FKA), avail¬ able as an option on the E66. The rear compartment air condition¬ er is located in the front area of the luggage compartment. The control and integration of the rear compartment air conditioning system in the IHKA refrigerant circuit is designed so that inde¬ pendent operation is possible for either the front or rear unit. Note: BMW Climate Control Systems may be Coolant (water) Temperature Regulated or Air Temperature Regulated depending on the model. E70 Dual Zone IHKA E70 Dual Zone IHKA Fresh air or recirculated air can be routed directly to the air ducts via the evaporator and appropriate bypass, without being routed through the system’s heater core. The airflow (fresh air or recirculated air) is first routed via the evaporator in the heating/ air-conditioning housing, provided that the A/C compressor has been activated, cooled and then heated to the reguired temperature via the heating system. Due to its dual section heater core, the IHKA allows separate and individual 2- zone, right/left temperature control. This is achieved in part, through the use of left and right tempera¬ ture sensors. The desired temperature is fine tuned via two water control valves (left/right). The water flow through the heater core is aided with the use of an auxiliary water pump in the case of vehicles with the N62 engine (the N52 engine has an electric water pump thus no auxiliary pump is need¬ ed) Index Explanation Index Explanation 1 IHKA, 2-zone 6 Ventilation air outlet, front center, left/right 2 IHKA operating unit with right & left temp, controls. 7 Ventilation air outlet, front left/right 3 Two inlet pipes to HWT, two water valves 8 Footwell air outlet, front left/right 4 Fresh air intake 9 Footwell air ducts, rear left/right 5 Defrost air outlet 10 Ventilation air outlet, rear left/right Note: E70 Dual Zone IHKA uses ten actuator motors and flaps. Climate Control Workbook 55 56 Climate Control Workbook E70 IHKA 4-zone with FKA rear automatic A/C System E70 Four Zone IHKA with FKA The 4-zone climate control system consists of the standard 2-zone IHKA plus: • Its own FKA controls • Four additional outlet temperature sensors • A separate rear blower • Air ducts and outlets in the B-pillars • Two separate PTC heating elements in the rear footwell air ducts • Three additional actuator motors for air flap control of the system (IHKA with FKA, total of thirteen actuator motors) Index Explanation Index Explanation 1 IHKA with rear automatic A/C system, 4-zone. 7 Defrost air outlet 2 IHKA, dual front tempera¬ ture controls 8 Ventilation air outlet, front left/right 3 FKA, dual rear tempera¬ ture controls 9 Ventilation air outlet, front left/right 4 Two inlet pipes to HWT, two water valves 10 Footwell air outlet, front left/right 5 PTC heating element in footwell air ducts rear left/right 11 Rear ventilation air outlet, center, left/right 6 Rear blower (FKA) 12 Ventilation air outlet, B-pillar left/right E66 Rear Air Conditioning FKA From E66 series launch, a Rear Compartment Air Conditioning system (FKA) may be installed as an option. The rear compartment air conditioner is located in the front area of the luggage compart¬ ment and consequently reduces the volume of the luggage com¬ partment by about 20 percent (incl. trim panels). The control and integration of the rear compartment air condition¬ ing system in the IHKA refrigerant circuit is designed so that inde¬ pendent operation is possible for either the front or rear unit. The air required for rear compartment air conditioning is drawn in via a particle filter (recirculated air filter) from the luggage compart¬ ment with the use of a rear blower fan. 3 2 1 The rear system shares some of the Main (front) A/C system’s components like compressor, condenser and dryer and the operate independently from each other separated by two refrigerant shut off valves. Operation of the rear air conditioning system from two separate control panels and takes place by means of push-buttons and rotary knobs, of which only those on the right are "intelligent." These two control panels must be matched with respect to each other; i.e. the right-hand control panel must be calibrated with the exact end stop values of the potentiometers of the left-hand control panel. (Refer to the relevant service information on TIS) The rear compartment air conditioning system additionally supplies cold air to an integrated refrigerator box. This refrigerator box should not be confused with the electrically operated refrigerator box that is optionally available also for the E65. Index Explanation 1 Pressure and suction refrigerant line. 2 Blower and recirculated air filter. 3 Rear compartment refrigerator box 4 Left/Right ducts to roof outlets. 5 Left/Right outlets in control units. Note: Filling mode can be activated via the diagnosis inter face for the rear compartment air conditioning sys¬ tem. In this mode, both refrigerant shut-off valves (front/rear) are opened, allowing complete recovery of the refrigerant charge. Climate Control Workbook 57 58 Climate Control Workbook E70 Third Row Heating/Ventilation The E70 with 3rd row seats uses a heating and ventilation system referred to as HB3SR. The blower is switched on and off using the button near the center air outlet. The air distribution at the ventila¬ tion air vents in the third row seats is controlled using a knurled adjusting wheel with control flap. A PTC heating element is activat¬ ed via the limit position switch operated by the knurled adjusting wheel. E70 HB3SR System General View E70 HB3SR Vent and control location Index Explanation 1 System unit for heating and ventilating the 3rd row of seats 2 Ventilation blower and heating for 3rd row of seats, recirculated air intake 3 PTC heating element 4 Auxiliary heating temperature sensor 5 HB3SR control unit Note: HB3SR is NOT a rear air conditioning system and it operates independently from the IHKA and FKA Systems.The only link with the vehi¬ cle electronics is for power management. IHKA Systems Water-based Temperature Controlled IHKA Although IHKA is available in single and dual zone, most current BMW vehicles are dual zone systems. Due to the split design of a dual section heater core, the dual zone IHKA allows for separate 2- zone right/left temperature control by varying the water temperature on either side of the system. The heater core uses two temperature sensors and the tempera¬ ture is controlled via two water valves (left/right) that regulate water flow through the system based on the reguested Driver/Passenger temperature settings. These water valves are electrically pulsed and are typically sprung open when deactivated. Typical Dual Zone Water Temperature Controlled System The water are valves pulsed to regulate temperature based on the following inputs: • Left/Right temperature settings • Left/Right heater core temperatures • Outside temperature • Interior temperature • “Y” factor An auxiliary water pump is used to ensure the adeguate volume of coolant through both sides of the heater core to comply with the system’s reguirements. This pump is Typically powered directly from the IHKA control module through a final stage output. IHKA K-BUS OUTSIDE TEMPERATURE SIGNAL The auxiliary pump is used to supply coolant for the REST feature of the IHKA, although not all models use one. Some current vehi¬ cles use electric main water pumps and no longer need auxiliary water pumps. The air-mass flow (fresh air or re-circulated air) is first routed via the evaporator in the heating/air-conditioning housing (provided that the compressor has been activated) to be cooled, dried and then heated to the reguired temperature via the heating system heater core. The air is cooled and dried in the evaporator at the same time and the condensation is led away via the drains of the heater/AC air box. Fresh air or re-circulated air can be routed directly to the air ducts via the evaporator and appropriate bypass, without being routed through the heating system heater core. Note: Current vehicles that use Water-based Temperature are E53, E6X, E70, E83. Climate Control Workbook 59 60 Climate Control Workbook Air-based Temperature Controlled IHKA The temperature for the best possible interior climate in an air con¬ trolled system is regulated with a mixer flap in this type of system. A water valve that controls the water flow rate through the heater core (as in the water base system) is not used in an air-based tem¬ perature control system. A temperature mixer flap is integrated in the heater/air box housing and is used for adjusting the reguested temperature. Index Explanation Index Explanation A Heating off 1 Heat exchanger B Heating on 2 Temperature mixer flap When the temperature mixer flap routes the fresh air or recycled air through the heater core completely, maximum heating capacity is realized. When it is not necessary to heat the air, the heater is cov¬ ered off by the temperature mixer flap and the air is deflected away. A corresponding proportion of cold air to warm air is mixed with the flap in the intermediate positions, thus achieving and controlling the out let temperature in the vehicle based on the reguested cus¬ tomer settings and calculated values. The temperature mixer flap is operated by a stepper motor which is controlled by the IHKA/IHKR control unit. This type of temperature control is used on the E85 as a single zone as well as in the E9X vehicles as a dual zone. E85 IHKS Temperature Control Flap Index Explanation 1 Evaporator 2 Mixed air flap 3 Heater core 4 Stepper motor, mixed air flap A disadvantage of this control system is the large package space it reguires. In the case of complaints ("poor heating output" or resid¬ ual heating in "cold" setting) particular care must be taken to ensure that the mixer flap rests snugly on the stops in the corre¬ sponding end positions. As in the water-based temperature control system (signal for water valves), the control variable signal Y is calculated from the tempera¬ ture set-point and the various temperature sensors (Y Factor). The respective position of the temperature mixer flap is derived from this signal. It also determines the position of the air distribu¬ tion flaps as well as the automatic blower output control when the automatic button is pressed. E90 AirTemperature Controlled System The temperature inside the vehicle is controlled by means of a master controller. Control is based on the nominal values set and the calculated actual value (the nominal values are the requested temperature settings). The actual value is calculated from the tem¬ peratures measured by the interior temperature sensor and the footwell temperature sensor. The lead parameter is calculated from the comparison between the actual value for the interior temperature and the corrected nominal value (calculated from temperature request, interior temperature and ambient temperature). Compared to the set specification, the interior temperature is raised in the cold so that a comfortable level is achieved even at negative temperatures, despite the temperature setting being unchanged. A separate temperature setting for the driver's side and the front- passenger side makes 2 mixer flaps necessary for a dual zone sys¬ tem. index Explanation 1 Stepper motor, air mixing flap, left 2 Stepper motor, air blending, front 3 Stepper motor, air mixing flap, right The temperature for the best possible interior climate in an air con¬ trolled system is regulated with a mixer flap in the heater/air condi¬ tioner. Coolant flow is constant in the heater core as the mass airflow is fed through the evaporator. As this happens, the air is cooled and dried (providing the air-conditioning system is switched on). The mixer flap then feeds the air completely or in part over the heating system heater core, depending on the desired temperature value set at the IHKA control panel the airflow is subsequently mixed again. The air-mass is then fed through the ventilation flaps and into the vehicle interior. Vent Temperature Stratification Stratification in the climate control system refers to the mixing of the air temperature at the outlet vents. Hot, warm or cold air can be adjusted as it comes out of the front or rear outlet vents no matter what main temperature setting was selected on the IHKA. This is realized by mixing hot and cold air with the use of blend air flap. Front stratification refers to the components necessary to adjust the dash outlet vent temperature to the occupant’s preference. Rear stratification refers to the rear passenger compartment air delivery vents. Thumbwheel adjusters on or near the vents are the typically con¬ nected to the mixing flaps mechanically (Bowden cable) or elec¬ tronically (Potentiometers and stepper motors). Climate Control Workbook 61 62 Climate Control Workbook Typical Stratification Process Stratification is realized mechanically and electronically: • Mechanical stratification is through the use of a Bowden cable connected from the air mixing flap to a thumbwheel adjuster mounted on or near the vent. The adjustment is done by manipulating the air mixing flap depending on: • Thumbwheel and Bowden cable position (mechanical) • Vent outlet temperature sensor readings • Occupant requested settings (Potentiometer position at the thumbwheel adjusters) • Occupant selected settings on the I Drive CID screen under climate control menu. E70 CID Vent Stratification Settings • Electronic stratification adjusts the air mixing flaps with the use Note: In vehicles with CID (E6X or E70) the air stratification of stepper motors. can be adjusted through the I Drive and CID screen at the climate control settings. The Y Factor Typical Y Factor Chart The reference variable Y Factor (in %) is derived from the compari¬ son of the actual interior temperature value with the corrected tar¬ get value = driver's choice + outside temperature application. Although air temperature controlled systems work in similar manner, in a coolant temperature controlled system: Y Factor of 0% = water valves closed = NO heating output. Y Factor of 100% = water valves open = FULL heating output. The master controller sends the signal to the two lower-ranking auxiliary controllers on the left and right. The auxiliary controller relieves the burden on the master controller in that it corrects inter¬ ference such as air volume and water flow fluctuations or coolant and fresh air temperature variations that would otherwise be notice¬ able as variations in the temperature in the passenger compart¬ ment. The opening time of the water valves is calculated from the differ¬ ence of the auxiliary controller set point and the actual heat exchanger temperature. The water valves are activated pulse-width modulated with a period duration of 3600 ms. This control variable Y represents the basis for further fundamental functions of the IHKA such as: • Automatic blower output control in the automatic program • Air distribution flap adjustment in the automatic program • Auxiliary water pump operation ON/OFF • Cold start interlock • Compensation of solar sensor influence MAXIMUM MAXIMUM COOLING HEATING 1 1 1 1 1 Radical Correction 1 1 1 Moderate 1 1 1 Radical Correction 1 1 1 1 1 1 Zone - Cooling i 1 1 1 Correction Zone 1 1 1 Zone - Heating 1 1 1 1 1 Compressor 1 1 Adequate 1 | 1 I 1 | Operation Cooling 1 Required for Power 1 l 1 1 Adequate | without 1 1 1 II Cooling iCompressori | | 1 1 1 Power 1 1 1 Operation 1 1 1 1 1 1 1 l 1 1 1 1 1 1 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 Y-FACTOR The lower the Y-factor number, the harder the system is working to cool down the interior; the higher the number, the harder the sys¬ tem is working to warm up the interior. In the middle region, the system is working to maintain the existing interior temperature. Note: It is not possible to view the Y-Factor parameter in all vehicles and the typical Y-range of 0 tol 00% temper¬ ature control has been extended from -200% to +300% to comply with current IHKA system func¬ tions. Climate Control Workbook 63 64 Climate Control Workbook Climate Control Components Climate Control Panel/Module (E90 IHKA) The control and operating module is the control center of the heating and air conditioning system. It is the point where all the necessary sensor data is processed and the reguired settings can be entered. Since the E90 a new feature of the control module is that it no longer directly controls all functions and components like in other models but rather makes use of other control modules for this purpose (distributed functions). The E90 IHKA panel is directly responsible for the following: • SZM switch input • Solar sensor input • Receives the rear stratification knob (rheostat) signal • Receives ventilation, footwell, and evaporator temperature sensor signals The IHKA panel indirectly receives • Condensation sensor signal via the K-CAN. The signal path is: Condensation sensor-> FZD => K-CAN ->IHKA Digital Motor Electronics (DME) Control Module The DME control unit performs the following functions: • Actuates the Engine cooling fan for cooling of the condenser. • Interfaces with the IHKA control unit via the bus network for the compressor release signal. • Interfaces with the IHKA control unit for operation of the engine’s electric water pump for the residual heat feature. Junction Box (JB) The junction box is extremely important to the IHKA system. It is responsible for the following functions: • Output signal for seat heating. The signal path is: SZM => ribbon cable => IHKA => K-CAN=> JBE => SHM/SMFA • Rear window defogger The signal path is: IHKA => K-CAN => JBE (relay) => Rear window defogger filters/grid • Blower motor operating voltage • Refrigerant control valve (in compressor) The signal path is: IHKA => K-CAN => JBE => Operating voltage for valve • Gateway to the PT-CAN for bi-directional communication between the IHKA and DME. The signal path is: IHKA <=> K-CAN <=> JBE <=> PT-CAN <=> DME • Receives the rear stratification knob (rheostat) signal • Receives refrigerant pressure sensor signal The signal path is: Pressure sensor => JBE => K-CAN => IHKA • Receives AUC sensor signal The signal path is: AUC sensor-> JBE => K-CAN => IHKA • Splice point for the ambient air temperature sensor The signal path is: Ambient air temperature sensor => hardwire => through JB => IKE Roof Control Panel (FZD) The roof control panel is used to relay the condensation sensor signal to the IHKA. It takes the signal from the condensation sensor and places it on the K-CAN. Car Access System (CAS) The CAS assigns a personal identification code to every remote control. The CAS transfers the personal identification code to the IHKA control unit via the K-CAN. The ID code “Key-based settings” (Key Memory) are stored in the IHKA control unit. When the vehicle is unlocked, the remote control unit used is rec¬ ognized. The settings stored for this unit are called up and execut¬ ed. While entering the sleep mode (run-down period), the current settings are stored for the remote control unit in use at that time. Car Communication Computer (CCC) If the vehicle is eguipped with a navigation system, the signals from the controller for selecting the menus and sub-menu are processed in the CCC. To actuate the CID (Central Information Display), the red-green- blue signals from the graphics processor are converted into Low Voltage Differential Signalling (LVDS) digital signals. Central Information Display The following control and display functions are selected and acti¬ vated with the controller in the CID (Central Information Display): • Air distribution setting - The defrost flaps, ventilation flaps and footwell flaps can be individually set in the air distribution sub¬ menu. • Automatic mode - The intensity of the IHKA can be set in the automatic mode submenu. In other words, the automatic influ¬ ence of the climate conditions outside the vehicle on the air volume and the opening angle of the flaps can be set to one of three different settings (low, medium, high). Center Console Switch Cluster (SZM) The center console switch cluster (SZM) is connected by means of a 14-wire ribbon cable directly to the IHKA control module. The commands from the SZM are then transmitted via K-CAN to the corresponding systems. The A/C control and operating unit is also responsible for activation of the LEDs for function and backlighting. Climate Control Workbook 65 66 Climate Control Workbook © (t (§) 0 © H 0 S E90 IHKA Diagram IHKA Inputs 68 Climate Control Workbook IHKA system performance relies on a network of sensors that input information to the controller in order to compensate and adjust all the variables that are involved in the control of the climate, in the vehi¬ cles passenger compartment. These sensors vary depending on eguipment options but are generally the following: • Interior Temperature Sensor • AUC Sensor • Solar Sensor • Condensation Sensor • Outlet Temperature Sensor • Refrigerant High Low Pressure Sensor • Evaporator Temperature Sensor • Heater Core Temperature Sensors Left Right • Ambient Outside Temperature E60 IHKA System Components Index Explanation Index Explanation 1 HKA controls / module with interior temperature sensor 19 A/C compressor 2 Instrument cluster (KOMBI) 20 Auxiliary water pump 3 Ambient temperature sensor 21 Heated washer jets , Left and Right 4 AUC sensor 22 Relay for heated rear window 5 Condensation sensor 23 Auxiliary Electric Heater (Not For US)I 6 Solar sensor 24 Fresh Air / air-recirculation flap motor Left 7 Refrigerant pressure sensor 25 Fresh Air / air-recirculation flap motor Right 8 Ventilation temperature sensor 26 Ventilation flap motor, Left 9 Potentiometers for rear compartment ventilation 27 Ventilation flap motor, Right 10 Heater core temperature sensors Left and Right 28 Cold air flap motor 11 Evaporator temperature sensor 29 Footwell flap motor, Left 12 Power distributor, front 30 Footwell flap motor, Right 13 Body Gateway Module (KGM) 31 Defroster flap motor 14 Digital Motor Electronics (DME) 32 Rear compartment flap motor (stratification) 15 Central Information Display (CID) 33 Blower with blower output stage 16 Multi-audio System Controller (M-Ask) LIN-bus Local interconnect network bus 17 Controller PT-CAN Powertrain CAN 18 Dual water valve K-CAN Body CAN Climate Control Workbook 69 70 Climate Control Workbook Interior Temperature Sensor The interior temperature sensor is a NTC type thermistor, typically mounted in the IHKA panel. To promote adequate airflow across the sensing element a small puller type fan is used. Fan and sensor work together provide an interior cabin temperature input to the IHKA control module. E60 IHKA Interior Temperature Sensor '"--T. AUC Sensor The AUC sensor, originally located in the lower right corner of the fan shroud, samples ambient air that has entered the engine com¬ partment. The sensor contains a gas sensor, which measures the level of oxidizable gases in air. These include hydrocarbons, NOx, SOx and CO. The AUC sensor sends a voltage signal to the control panel/module according to the concentration of these pollutants. If a high level of pollutants is detected, the control panel/module activates the recirculating air mode as follows: • In heating mode, recirculating air is used for a maximum of 3 minutes. If the level of oxidizable gases drops to an acceptable point before the time limit is reached, the IHKA system switches back to fresh air intake. If air quality has not improved at the end of the time limit, the system switches to fresh air briefly and then back to recirculat¬ ing mode for another 3 or 10 minute period. E90 AUC Sensor Location Note: Operating strategies of the AUC sensor may vary from model to model. In cooling mode, recirculating air is used for a maximum of 10 minutes. Solar Sensor The solar sensor records the light intensity of the insolation to which the vehicle interior is being subjected separately for the right and left-hand sides. The influence of insolation on the temperature in the vehicle interior is compensated for in automatic mode by means of temperature specified value control intervention. E60 Solar Sensor Typically located in the center of the dashboard or integrated to the rain light sensor assembly like on E70. The solar sensor consists of a light sensitive diode that provides the IHKA module with inputs of sunlight intensity. The input is used as a measure of the solar heating effect on vehi¬ cle occupants. The sensor signals will influence blower output, air stratification and ventilation flap operation. Condensation Sensor Introduced with the E60 model, this sensor varies its frequency out put in response to the presence of humidity and temperature in the windshield area. This information is sent to the IHKA control module via a digital signal with a varying frequency. This informa¬ tion is evaluated by the IHKA control module, which then imple¬ ments a series of countermeasures to prevent windshield fogging. On the current E60 the condensation sensor is mounted under the rain light sensor (RLS) on the mirror base. Other names for the condensation sensor are Mist, Fogging, and Humidity sensor. E60 Condensation Sensor Index Explanation 1 Rain-light sensor 2 Condensation sensor The sensor is located beneath the RLS on the windshield below the cover for the base of the rearview mirror. A special locating tool is used to install the new sensor, this tool is supplied with the replacement sensor. The sensor is affixed to the windshield with an adhesive. If the sensor needs to be removed from the windshield it must be replaced. Climate Control Workbook 71 72 Climate Control Workbook Condensation/Mist Sensor Index Explanation 1 Sensor electronics 2 Pin connection 3 Moisture measuring cell 4 Well for laser adjusted resistors When moisture is detected by the Condensation Sensor, the fol¬ lowing occurs: Rain/Driving Light Solar Sensor The rain/driving light solar sensor RLSS of the E70 is clipped into a retaining ring beneath the windshield mirror base cover. The rain/driving light solar sensor separately records the insolation act¬ ing upon the vehicle occupants for the left and right halves of the vehicle. It generates two signals that are proportional to the insola¬ tion acting upon the vehicle occupants. The temperature rise due to heat from sun radiation in the vehicle interior is compensated for in automatic mode by means of tem¬ perature specified value control intervention. The sensor signal is read in by the FZD via the LIN bus and relayed to the IHKA via the K-CAN. The signals are used by the IHKA to regulate the left and right air volume and ventilation temperature. • Defroster Flaps open further • Fresh Air Flaps open 100% • Blower speed is increased • Footwell Flaps are closed • Temperature increases • Evaporator Temperature threshold goes to minimum These measures are implemented one after another until wind¬ shield fogging is eliminated. Further steps are initiated if one meas¬ ure proves to be ineffective. After successfully eliminating wind¬ shield fogging, the measures are gradually cancelled in steps. E70 RLSS Sensor Outlet Temperature Sensor NTC Sensors are installed in the air outlet vents in order to monitor air vent temperature delivered. This is a crucial parameter in the cal¬ culation of the ideal outlet temperature with regard to the request¬ ed temperature value. Depending if the system is single, dual zone or four zones like E70, these sensors operate in the same manner and in all cases are located in the middle of the air delivery. In the case of a four zone system the driver, front passenger and rear seat passengers may have their own individual temperature settings. This is in part possi¬ ble because of the use of these individual outlet vent temperature sensors and PTC heaters in the rearfootwell vents. Index Explanation 1 E70 FKA rear center ventilation outlet 2 Left/right rear ventilation temperature sensors 3 Left/right rear air stratification potentiometer 4 Left/right rear ventilation manual shut-off flap The vent temperature is also adjusted locally at the dash face vents or the rear delivery vents by means of the stratification potentiome¬ ter thumbwheel adjusters. This is still done with a cable in some current vehicles like X3. Refrigerant High/Low Pressure Sensor The pressure sensor is mounted on the liquid reservoir and sends out a voltage signal depending on the pressure in the air condition¬ ing system. This signal is transferred in the form of a telegram to the digital motor electronics (DME). In turn, the DME outputs the control volt¬ age for the output stage of the auxiliary fan, thus activating the cor¬ responding fan stage (speed) or shutting down the compressor to prevent damage in response to very high pressures. Activation of the auxiliary fan is also influenced by an excessively high coolant temperature. On vehicles equipped with a condenser module (filter dryer inte¬ grated in the condenser), the pressure sensor is installed in the high pressure line between the condenser and expansion valve. On various automatic transmission vehicles such as the E65 and E60, the auxiliary fan is also activated by excessively high transmis¬ sion fluid temperature. The higher fan stage is then generated in this case. Climate Control Workbook 73 74 Climate Control Workbook Evaporator Temperature Sensor The sensor is installed between the evaporator fins or arranged behind the evaporator in the flow of cold air. Depending on the type of system in the vehicle, the temperature at the evaporator is moni¬ tored as the regulator switches the electromagnetic clutch of the compressor on and off or signals the compressor control valve (clutchless compressor) as reguired. This prevents the evaporator fins from icing up due to frozen condensed water. Controlled via the IHKA control unit, the sensor generally switches off the compressor at a temperature of about. 1°C and on again at about. 3°C. In connection with the output-controlled compressors with mag¬ netic clutch, the sensor only serves as a protection function in the event that the temperature at the evaporator drops below 3°C. Conseguently, the compressor remains switched on almost perma¬ nently. With the interior temperature set at comfortable levels, the compressor is generally switched off by the electromagnetic clutch only at outside temperatures below about. 6°C. In the case of output-controlled compressors without an electro¬ magnetic clutch, if there is a threat of the evaporator icing up, the IHKA will correspondingly change the pulse-width-modulated con¬ trol signal via the electric control valve in the compressor. Conseguently, the compressor output is reduced in the direction of zero. Icing of the evaporator can be recognized by decreasing air volume at the air outlet vents. Note: Evaporator temperature sensor is shown by #6 in the illustration. E70 IHKA Housing Index Explanation 1 IHKA housing 2 Fresh air intake 3 Expansion valve coolant connection 4 Heater core water connection 5 Evaporator 6 Evaporator temperature sensor 7 Heater core 8 Electric PTC auxiliary heater (not for US vehicles) 9 Heater heater core temperature sensor Heater Core Temperature Sensors Left/Right Heater core temperature is monitored to insure the correct desired temperature at the vents. Heater core temperature along with ambient, vent and evaporator temperatures are the main parame¬ ters utilized to calculate Y Factor. Thus we control the coolant flow though the heater core by varying the heater valve opening on a water based system. The Air based System has no need for a water valve because it controls temperature by adjusting the air mixing flap. As an added benefit we also monitor heater core temperature in other to maintain a safe range of operation and in case of over heating the heater valves can be shut off. In IHKAthe individual temperature readings are of crucial impor¬ tance and necessary in other to be able to separately adjust the outlet temperature for the driver and the passenger. This calls for the installation of two heater core temperature sensors. E60 Heater Core Temperature Sensor Ambient Outside Temperature The ambient temperature sensor is similar to interior, evaporator, heater core and outlet vent sensors in their operation. An NTC neg¬ ative temperature coefficient sensor as temperature goes up resist¬ ance goes down. The temperature sensor is located at the front end of the vehicle in front of the condenser and it is responsible for reporting ambient temperatures to all systems that reguire the reading. E60 Ambient Temperature Sensor Climate Control Workbook 75 76 Climate Control Workbook Workshop Exercise - Climate Control Input Diagnosis Using an Instructor assigned vehicle, hook-up the BMW Diagnostic Equipment and perform a complete short test. Hook-up the A/C service station, turn vehicle on and set IHKA to Auto. Allow system to stabilize while monitoring manifold gauges. 1. Check cabin/vent temperature and verify proper system per¬ formance. 5. Place the rear temp, flap position at 0%. What temperature is registered at the rear vent outlet? 2. Access climate settings in the CID and modify Air Distribution and Automatic mode settings. What changes did you observe? 6. Set the driver side temperature to the hottest setting on IHKA. Which flap registered the change and what does it read? 3. Access Diagnosis Request for front and rear vent tempera- - ture, adjust the stratified air potentiometers for both and 7 . Set the passenger side temperature to the coldest setting. observe vent temperature readings. Which flap registered the change and what does it read? In what module did you locate vent temperature? 4. Install a thermometer in the outlet being manipulated and q Monitor what changed and register your findings, answer the following questions. What does the flap position at 100% produce at the rear vent _ outlet? Workshop Exercise - Climate Control Input Diagnosis Using the Instructor assigned vehicle, hook-up the BMW Diagnostic Equipment and perform a complete short test. Hook-up the A/C service station, turn vehicle on and set IHKA to Auto. Allow system to stabilize while monitoring manifold gauges. 9. Access Diagnosis Request for the A/C pressure sensor and 13. What did the pressure reading on the BMW Diagnostic compare the displayed value to the manifold gauge readings. Equipment display? What module monitors the pressure sensor and why? 10. Did the reading match the high side reading on the manifold gauge? 14. Complete a short test and note which modules stored a fault. Which module(s) stored a fault for the pressure sensor and why? 11. Unhook the pressure sensor with the A/C working and observe changes in system operation. Did the sensor value change? 15. Restore the system to normal operating condition and clear any faults. 12. How did the A/C system pressures respond? Climate Control Workbook 77 78 Climate Control Workbook Workshop Exercise - Climate Control Input Diagnosis Using an Instructor assigned vehicle, hook-up the BMW Diagnostic Equipment and perform a complete short test. Hook-up the A/C service station, turn vehicle on and set IHKA to Auto. Allow system to stabilize while monitoring manifold gauges. 16. Place the system in auto mode and set left and right tern- 20. Leave the system in auto mode and access diagnosis perature requests to 65 degrees. Access diagnosis request request for the AUCII sensor, for the solar sensor. What does the sensor value display? What can you do to trick the Solar Sensor to react? 17. Did the sensor value change? 21. In which module did you find the AUC sensor and why? 18. How did the system respond to solar variation? 22. How can you trick the AUC sensor to react? 19. In which module did you find solar sensor information and why? Workshop Exercise - Climate Control Input Diagnosis Using an Instructor assigned vehicle, hook-up the BMW Diagnostic Equipment and perform a complete short test. Hook-up the A/C service station, turn vehicle on and set IHKA to Auto. Allow system to stabilize while monitoring manifold gauges. 23. Manipulate the sensor and observe changes in sensor values and system operation. 27. Would such a condition set a fault? Why or why not? What changes in the system operation did you observe? 28. Carefully place a cup of warm water on the dash to fog up 24. Access diagnosis request for the interior temperature sen- the windshield, sor and note current values. In which module did you find interior temperature and why? - 29. Where is a good location to test the mist sensor signal? 25. Restrict the air inlet to the interior temperature sensor and observe changes in sensor values and system operation. What happened? _ 30. What eguipment and V Cable # can you use to monitor the 26. Could a build-up of dust/debris or a blockage at the fresh air m ' st sensor signal? inlet cause a system performance complaint? _ 31. Monitor the Mist Sensor change. What type of signal did you get from the mist sensor? Climate Control Workbook 79 IHKA Outputs Based on the feedback from the IHKA inputs the system calculates the Y factor and reacts to the desired requested temperature and or conditions detected to operate the following out put devices to deliver optimum performance. Compressor clutch/Compressor control valve Blower motor/Final stage Water valves Auxiliary water pumps Electric water pump Auxiliary fan Stepper motors Compressor Operation The compressor control circuit varies between systems. There are three basic methods for compressor control. • The compressor clutch coil receives power from the KL 87 terminal of a relay which is ground controlled by ECM (DME). • The compressor clutch is powered directly by the climate con¬ trol module. A final stage in the control module sends power directly to the compressor clutch. The relay and additional wiring are eliminated. • Constantly engaged compressors are usually variable dis¬ placement units. The compressor has a swash plate that can vary the amount of compression on the refrigerant with the input from a control valve. The compressor valve is controlled and powered by the junction box in most resent models but the command comes from the IHKA module. Blower Motor/Final Stage The fresh air/recirculated air blower is flange mounted to the right side of the IHKA housing. The specified voltage for the blower is provided by the IHKA (Master) as a defined control signal (PWM signal) via a single-wire interface of the blower output stage (Slave). The blower motor is actuated by the blower output stage depend¬ ing on this variable control signal. The line connections from the IHKA to the final stage are monitored by the IHKA. The blower and the output stage can be replaced separately. See appropriate workshop systems documentation. The motor voltage is limited to 12.5V by the software. If an overload is detected at the output stage output or temperature protection is activated, the engine output is reduced. Index Explanation 1 IHKA blower housing 2 blower output stage Climate Control Workbook 81 82 Climate Control Workbook Water Valves Temperature regulation on IHKA systems is accomplished by sole¬ noid actuated water valve(s). The valve(s) are normally held open by spring pressure (fail safe), and are electrically pulse width modulat¬ ed by the IHKA control module (B+) signal to regulate the flow of hot coolant through the heater core(s). The water valve(s) are pulsed according to the Y-factor, which is cal¬ culated from the following inputs: • Desired temperature reguest (left and right if eguipped) • Interior temperature • Heater core temperature(s) • Ambient air temperature • Blower speed reguest When the desired temperature E60 Water Valve calls for maximum heat, the water valve(s) do not receive pulses and are mechanically sprung open. Similarly, when maximum cooling is reguested, the IHKA control module powers the water valve(s) completely closed. The water valves used on the water temper¬ ature controlled dual zone IHKA systems have one inlet and two outlets on a single valve. Water Valve (Air Temperature Control) A water valve that controls the water flow rate through the down¬ stream heater core is not used for setting the temperature in an air- based temperature control system but rather a temperature mixer flap is integrated in the heater/air conditioner. A single water valve is typically used to control the amount of heat sent to the heater core on an Air Temperature Controlled Systems, although most current vehicles (E85, E9X) don’t use one. To control the temperature desired by the dual zone climate control system, air mixing flaps are used. Auxiliary Water Pumps Typically used on Water Regulated Systems. Electrically powered auxiliary coolant pump ensure that an adeguate supply of hot coolant is always available to the heater core(s). The IHKA control module operates the pump directly or through a relay by supplying the ground circuit. Some current vehicles use electric water pumps and don’t need to use an auxiliary pump to maintain adeguate coolant flow through the heater core. E60 Auxiliary Water Pump Electric Water Pumps The current N52 and N54 engines are equipped with electronically controlled water pumps. Electric water pumps decreased warm up time while enhancing power output and fuel economy. When the residual heat (REST) function is activated, the IHKA con¬ trol unit interfaces with the DME control module to activate the electric water pump. The water pump allows hot/warm coolant to flow through the heater core and warm the passenger compart¬ ment. The coolant pump of the N54 engine is an electrically driven cen¬ trifugal pump with a power output of 400W and a maximum flow rate of 9000 l/h. This represents a significant increase in power of the electric coolant pump used in the N52 engine, which has a power output of 200 W and a maximum flow rate of 7000 l/h. The DME (ECM) uses the engine load, the operating mode and the data from the temperature sensors to calculate the required cooling output. Based on this data, the DME issues the correspon¬ ding command to the electric coolant pump. The electric coolant pump regulates its speed in accordance with this command. The system coolant flows through the motor of the coolant pump, thus cooling both the motor as well as the electronic module. The coolant lubricates the bearings of the electric coolant pump. Electric Water Pump Note: The pump must be filled with coolant when removed for service to prevent any corrosion. Also, the pump impeller must be turned by hand before installation to ensure the pump is not seized. Index Explanation 1 Pump 2 Electric Motor 3 Electronics for coolant pump Climate Control Workbook 83 84 Climate Control Workbook Map Thermostat In view of the fact that an intelligent heat management system has an influence on fuel consumption, exhaust emissions, performance and comfort according to engine temperature, this data-map ther¬ mostat was developed for use with such a system. When the over-temperature light in the instrument cluster is on (120°C), the fan is run in the overrun function. This signal is provid ed to the ECM (DME) via the CAN bus. When this occurs, the fan is run at a frequency of 10Hz. The data-map thermostat successfully integrates modern engine management electronics. That combination is achieved by placing an electrically heated resistor in the expanding element of the ther¬ mostat. That data map is determined, for example, by the following param¬ eters: • Engine load • Engine speed • Vehicle speed • Intake-air temperature • Coolant temperature Auxiliary Fan Control (from 99 MY) The auxiliary fan motor incorporates an output final stage that acti¬ vates the fan motor at various speeds. Typical Auxiliary Fan Control System RADIATOR OUTLET TEMPERATURE SENSOR OUTPUT STAGE iiii’.J |-j LaJ LJ 1_1 1-1 i—J = L__J i .... i AUX FAN OUTPUT STAGE/MOTOR IHKA SIGNALING VIA CAN BUS: -Variable Speed Auxiliary Fan Control - IHKA on - Compressor Activation Status The auxiliary fan is controlled by the ECM. The motor output stage receives power and ground and activates the motor based on a PWM signal (10-IOOHz) received from the ECM (DME).Thefan is activated based on the following factors” • Radiator outlet temperature input exceeds a preset tempera¬ ture. • IHKA signaled via K and CAN bus based on calculated refrig¬ erant pressures. • Vehicle Speed • Batte ry Vo Itag e Leve I Stepper Motors BMW IHKR and IHKA Climate Control Systems use 12 volt DC electric stepper motors to operate many of the air inlet, air distribu¬ tion and temperature mixing flaps. While different types of stepper motors are used on different vehicles, they all share many desirable characteristics: • Lower power consumption • Operate in both directions • They can be started and stopped in any position • They provide quick movement • They move in precise increments • They do not require feedback potentiometers to determine position • They remain in position when shut off • They have long service life Conventional Stepper Motors Until the E38 was introduced, the stepper motors used in IHKR and IHKA climate control systems did not contain electronic com¬ ponents, and only 3 part numbers were needed to service all the motor assemblies. These motors consisted of copper wire coils wrapped around iron cores (pole pieces), and permanent magnet rotors, all attached to a high-reduction mechanical gearbox. The system electronic control components were located inside the cli¬ mate control module assembly. There up to 4 sets of winding in these motors. This circuit arrange¬ ment requires from 5-6 wires between the control module and the stepper motor. These motors were used on early climate control systems and are still used on some vehicles for fresh air flap opera¬ tion. “Smart” Stepper Motors Starting with the E38 climate control system, some of the control module electronics were moved into the stepper motors, making the E38 motors (except the fresh air flaps motor) substantially dif¬ ferent from the “conventional” stepper motors we’ve already dis¬ cussed. These “Smart” stepper motors use only three wires for operation. There is a power, a ground and the third wire for the “M” bus sig¬ nal. The “M” bus is used to send messages to the stepper motors. The commands or “messages” are sent by the climate control module. The stepper motors contain processors which will “inter¬ pret” the bus messages and actuate the stepper motors to the cor¬ rect position. Typical M-bus Diagram The M-bus stepper motors are different and have a different part number. They all feature a fixed programmed address and must therefore be installed in no other position than on the correspon¬ ding air flap, they cannot be interchanged and must be replaced with the same part number as was originally equipped. Climate Control Workbook 85 86 Climate Control Workbook The operating instructions issued to the smart stepper motors by the control module are much more sophisticated than with con¬ ventional stepper motors. The sequence of events appears below: ___.. . _ , M E38 M-bus Stepper Motors The control module determines that a flap position must change It issues a “wake-up call” to alert the stepper motors that a command is coming It “names” the motor that is to respond to the command It issues the command signal, e.g. “move 15 steps clockwise” All the stepper motors “hear” the command Only the stepper motor that “hears its name” follows the com¬ mand The “named” stepper motor then informs the control module that it has carried out the command DRIVER'S SIDE 72 0*F 1 6S0T ■L. 'll ML. nj ir^~n * $ | rri " 1, i m tti - REAR OUTLET -FACE VENT - FOOTWELL - FACE VENT -MIXING - DEFROST - MIXING - RECIRCULATING - FOOTWELL E65 Stepper Motors The E65 IHKA has a total of 11 stepper motors, 1 Rapid action motor for the fresh air flap and 10 “Smart” Stepper motors for all other flaps Each of these motors contains an integrated circuit (MUX- 4 chip) in the plug connection housing. This 1C controls the winding of the motor and is linked by a M-Bus. All stepper motor drives are controlled by the IHKA control module over the M-Bus. Note: Faults (blockages) reported by the drives are stored in the IHKA control module, which responds by dis¬ continuing control signals to the motor in question. Each drive has a permanent address (stored on the chip) which is a unique identifier for the individual motor (for bus communication). The stepper motors are all different and are not interchangeable. E60 Stepper Motors 7 J 6 E60 Stepper Motors The E60 IHKA system uses 9, MUX5 motors (multiplex motor type 5). These stepper motors have different part numbers, are connected to the LIN Bus in parallel and are not interchangeable. The LIN Bus replaced the M-Bus. This bus circuit consists of 2 three wires, power (B+), ground and the LIN bus signal wire. The stepper motors for the fresh air/recirculation air flaps are designed as high speed motors. This system does not use any bowden cables for flap actuation. 3 j 4) ZJ Index Explanation Index Explanation 1 Heater Core Temperature Sensor (RH) 7 Stepper Motor, left side ventilation 2 Stepper Motor, right footwell 8 Stepper Motor, fresh air/re-circulated air (LH) 3 Stepper Motor, fresh air/re-circulated air (RH) 9 Evaporator Temperature Sensor 4 Stepper Motor, right side ventilation 10 Stepper Motor, defrost 5 Stepper Motor, air stratification 11 Stepper Motor, left footwell 6 Stepper Motor, rear compartment (center) 12 Heater Core Temperature Sensor (LH) Climate Control Workbook 87 88 Climate Control Workbook E9X Stepper Motors The current E9X IHKA systems utilizes eight stepper motors that are wired in series for climate control operation. The IHKA control module also operates the stepper motors via the LIN-bus. • All eight stepper motors can be replaced without removing the dashboard or A/C housing. • Seven of the eight stepper motors used are identical (same part number). • A different stepper motor is used only for the fresh air/recircu¬ lation motor. “See the Service Information section”. • Flap motors are wired in series. • Each flap motor has a measuring resistance of about 1 ohm. E90 Stepper Motors LH Index Explanation Index Explanation 1 Stepper Motor, Ventilation Flap 5 Stepper Motor, Air Blending, Rear 2 Stepper Motor, Defroster Flap 6 Stepper Motor, Footwell 3 Stepper Motor Air Mixing Flap, Right 7 Stepper Motor, Air Mixinq Flap, Left 4 Stepper Motor, Fresh / Recirculating Air 8 Stepper Motor, Air Blending, Front E90 Stepper Motors RH Each flap motor is connected to its predecessor via this measuring resistance. For this reason, troubleshooting must be performed in the order stipulated in the schematic circuit diagram. A new gener¬ ation of stepper motors is used in the E90/E91/E92/E93 systems as well as in the current E70. These stepper motors feature two LIN bus connection lines (input/output). A motor has only one LIN-bus input on the wiring harness (foot-well motor). The motors are connected in series (the foot-well motor is the last motor in the series connection). Also in this case there are two different stepper motor versions. The motor with the designation EFB with IQ resistor, is used for all air flaps except the fresh air flap as well as in IHR and IHKR for the central (mechanism) kinematics. EAB Stepper Motor The motor with the designation EAB is used for the fresh air flap and the central kinematics (Air Distribution Mechanisms). The EAB motor varies its speed corresponding to the force applied at the flap. Faster at a low load force and slower at a high load force (with no IQ resistor). EAB Stepper Motor EFB Stepper Motor The EFB motor has a constant displacement speed and a defined moment. The EFB motors are all identical and must therefore be programmed. The air flap motors are connected in series. A IQ measuring resistor is installed in each air flap motor. The following air flap motor is connected to the one before it via this measuring resistor or shunt through the LIN-bus. The motors must be con¬ nected only in the seguence as shown in the schematic circuit dia¬ gram and electronically addressed for proper system operation. EFB Stepper Motor Climate Control Workbook 89 E70 Stepper Motors 90 Climate Control Workbook vE) <*) vD si) Actuator motors IHKA IHKAw/FKA 1 Fresh air/recirculated air, actuator motor V V 2 Dynamic pressure compensation, actuator motor V V 3 Defrost, actuator motor V V 4 Left/right front ventilation, actuator motor V V 5 Right/left front footwell, actuator motor V V 6 Right/left front air stratification, actuator motor V V 7 Right front ventilation, actuator motor V V 8 Left front footwell, actuator motor V V 9 Right front air stratification, actuator motor V V 10 Left/right rear air stratification, actuator motor V V 11 Left rear footwell, actuator motor Not used V 12 Right rear footwell, actuator motor Not used V 13 Right rear air stratification/shut-off, actuator motor Not used V E70 Stepper Motors The IHKA actuator stepper motors used on the E70 are the same as in the E9X. They are all designed as identical components and are actuated by the IHKA via the LIN bus. When an actuator motor is being replaced it must be ensured that the correct plug is connected to the relevant motor from the wiring harness end. The plug order can be found in the wiring diagram. Then an addressing run must be started using the BMW diagnos¬ tics system. The IHKA detects the actuators that are connected in series and assigns an address to the new motor if necessary. The actuation of the addressing run is integrated in the diagnostics system in the service function (re-address body, heating/air condi¬ tioning functions, flap motors). A function test (reference run) is also integrated in the diagnostics system, with which the opera¬ tional capability and the adjusting path of the motors can be tested. Replacement of a Stepper Motor After replacement, the stepper motor must be addressed. The addressing procedure is initiated with BMW Diagnostic Eguipment, The IHKR or IHKA control unit automatically assigns the address to the flap motor. The motor recognizes its assignment (address e.g. footwell motor) based on an addressing current. This arrangement makes it possible to use a standard motor for all air distribution flaps. The motor must not be turned by hand as this would pose the risk of irreparably damaging the electronics or the gear mechanism. IHKA with Rear Automatic Air Conditioning, 4-zone, Overview of Air Distribution Flaps Index Explanation 1 Actuator motor, fresh air/recirculating air 2 Actuator motor,dynamic pressure compensation 3 Actuator motor, defrost 4 Actuator motor, front left ventilation 5 Actuator motor, front right footwell 6 Actuator motor, front left air stratification 7 Actuator motor, right front ventilation 8 Actuator motor, left front footwell 9 Actuator motor, right front air stratification 10 Actuator motor, left rear air stratification 11 Actuator motor, left rear footwell 12 Actuator motor, right rear footwell 13 Actuator motor, right rear air stratification/shut-off 14 Housing internal non-return flaps Climate Control Workbook 91 92 Climate Control Workbook Workshop Exercise 1 - Climate Control Stepper Motor Diagnosis Using an instructor assigned E9X or E70 vehicle, hook up BMW Diagnostic Equipment, with Key ON and Engine and IHKA OFF. Following repair procedures, gain access to JB/JBE, Blower Motor and Final Stage, A/C Housing and Stepper Motors. 1. Unhook one stepper motors and complete a SHORT TEST. 4. What pre-conditions must be observed when Re-addressing the List any fault/s set below? stepper motors? _ 5. Are all displayed stepper motor position values from 0 to 100%? 2. Go to Service Functions and Re-address the stepper motors _ to follow the test plan. 3. List the Stepper Motors in their correct order in the following 6. List the values displayed for each stepper on the “ Pre ” sec- chart. tion of the chart. 7. Proceed with the Test Plan to test all the stepper motors until all fault codes are justified. 8. What conclusion was determined by these tests? Workshop Exercise 1 - Climate Control Stepper Motor Diagnosis Student instructions: Using an E9X or E70 vehicle, hook up BMW Diagnostic Equipment. 9. Reconnect the stepper you disconnected and re-address 1 4. Re-assemble the vehicle, restore the system to normal them again. operating condition and clear any faults. 10. Are all values displayed this time with in 0 and 100%? _ 11. List the values for each stepper motor under “Post" on the chart provided. 12. Why did the other stepper motors malfunction with just one stepper disconnected? 13. Where did you find the correct order that the steppers are sup¬ posed to be in? Climate Control Workbook 93 94 Climate Control Workbook Workshop Exercise - Climate Control Output Diagnosis (BUG1) Student instructions: Using an instructor assigned vehicle, hook up BMW Diagnostic Equipment. 1. Perform a short test on the IHKA system and list any fault 5. Perform an Air Distribution Test Plan next, codes found below. Is the Stepper Motor order correct? 2. Verify the system operation and list your findings below. 6. Work through the Test Plan to come to a conclusion to the problem. 7. Did the Test Plan help your diagnosis and what do you think the problem is? 3. Following repair procedures, gain access to JB/JBE, Blower - - - Motor and Final Stage, A/C Housing and Stepper Motors. n x x , , , x , 8. Start the test plan for re-addressing the stepper motors. 9. Verify they are connected and positioned properly. 4. Go to Function Selection and test temperature specification. - Is this function working properly? _ - 10. Re-address the stepper motors, Quick Delete and Short _ Test. Is the system working properly? Workshop Exercise - Climate Control Output Diagnosis (BUG2) Student instructions: Using an instructor assigned vehicle, hook up BMW Diagnostic Equipment. 1. Perform a short test on the IHKA system and list the fault 5. Complete the test plan for re-addressing the stepper motors, codes found below. List your findings below. 2. What do these fault codes indicate? 6. How would you find and correct the problem? List your actions below. 3. Verify system operation and list your findings below. 4. Following repair procedures, gain access to JB/JBE, Blower Motor and Final Stage, A/C Housing and Stepper Motors. 7. After fixing the problem re-addressing the stepper motors, erase fault codes and short test. List any new fault codes below. Climate Control Workbook 95 96 Climate Control Workbook Workshop Exercise - Climate Control Output Diagnosis (BUG3) Student instructions: Using an instructor assigned vehicle, hook up BMW Diagnostic Equipment. Customer complaint is temperature regulation. 1. Manipulate the IHKA to verify system operation. 6. Where is a good location to tap in to the water valve signal? What problem, if any was evident from your inspection? 2. Perform a Short Test on the vehicle. List any Fault Codes present in the system below. 7. Using the appropriate brake-out box and V cable connect the scope to verify the water valve is getting the correct signal. 8. What type of signal did you get? 3. Manipulate the temperature settings at the IHKA and monitor both heater core temperature sensor signals. What seems to be the problem with the system? 9. Manipulate the IHKA settings and observe the water valve signal for change. Is the problem electronic or mechanical? 4. What type of Temperature Control System are you working on? - 10. Would such a condition set a fault? and Why? 5. Is this valve Ground Controlled or Power Controlled on this vehicle? 11. Based on instructor evaluation, repair and retest the vehicle or move on to the next exercise. 98 Climate Control Workbook IHKA Functions and Features BMW vehicles are equipped with various versions of climate con¬ trol systems. Regardless of the version used, the objectives are basically the same. The climate control system is designed to per¬ form the following functions: • Remove heat from the passenger compartment when ambi¬ ent temperatures are above the drivers comfort zone. • Add heat from the passenger compartment when ambient temperatures are below the drivers comfort zone. • Dehumidify the air entering the passenger compartment. • Defrost front and rear windows for optimum vision and safety. • Remove contaminants from incoming air (with microfilter-if equipped). In addition to the above functions there are additional sub systems and additional features. These systems and features are not avail¬ able on all models. These features include: • Washer jet heating • Windshield base heating • “Rest” feature (residual heat) • “Service Station” feature • Parked car ventilation • Automatic Air Recirculation (AUC) • Cold start arrest E70 IHKA Buttons Index Explanation Index Explanation 1 Driver seat heater and ventilation 8 Blower speed/REST Feature 2 Left and right temperature controls 9 Rear defog 3 Passenger seat heater and ventilation 10 front defrost 4 Passenger Air duct selection button 11 Automatic mode button 5 MAX AC Button 12 Interior temperature sensor 6 AC button 13 Driver Air duct selection button 7 AUC (Auto air recirculation) Air pressure compensation 100 Climate Control Workbook E9XIHKA Functions The IHKA used in the current E9X vehicles have the following functions: • Temperature control • Evaporator control • Air distribution setting • Airflow control • Sunlight adaptation (solar sensor) • MAX cooling • Residual heat • Defrost function • AUTO function • Heated rear window • OFF • Air recirculation mode • Automatic air-recirculation control • Condensation sensor program • Convertible Mode (E93) Temperature Control The temperature for the best possible interior climate is regulated with a mixer flap in this (air based) heater/air conditioning system. The air-mass flow is fed through the evaporator. As this happens, the air-mass flow is cooled and dried (providing the air-conditioning system is switched on). The mixer flap then feeds the air-mass flow completely or in part over the heating system heater core (depend¬ ing on the desired temperature value set at the IHKA control panel). The airflow is subsequently mixed again. The air-mass flow is then fed through the ventilation flaps and into the vehicle interior. The temperature inside the vehicle is controlled by means of a master controller. Temperature Control is based on the nominal val¬ ues set and the calculated actual value (the nominal values are set with 2 temperature selector knobs). The actual value is calculated from the temperatures measured by the interior temperature sensor and the footwell temperature sen¬ sor. The lead parameter is calculated from the comparison between the actual value for the interior temperature and the corrected nominal value (calculated from temperature request, interior temperature and ambient temperature). Compared to the set specification, the interior temperature is raised in the cold so that a comfortable level is achieved even at negative temperatures, despite the temperature setting being unchanged. The ambient temperature is transmitted to the IHKA control unit via the K-CAN. The separate temperature setting for the driver's side and the front-passenger side makes 2 mixer flaps necessary. Evaporator Control The evaporator temperature is regulated by means of the evapora¬ tor temperature sensor and the expansion valve. The evaporator temperature is set to the predefined specification of 2°C (35.6°F). Lower temperatures are not possible due to the risk of icing. If the function gradual evaporator control is encoded, the nominal value for the evaporator temperature will be calculated between 2°C and 7°C (35.6°F and 44.6°F). The specification depends on the ambient temperature, the ventilation temperature and the refrigerant pressure. A variable evaporator control reduces dehu¬ midification. This enhances comfort for it reduces the risk of mucous membranes drying out. Air Distribution Setting For the best possible operation of the air distribution, it is important for the manually adjustable air vents to be open. Occupants have the possibility of allowing the air distribution to be decided by the automatic program (AUTO button). Alternatively, individual, personal settings are possible through manual selection (defrost, ventilation, footwell). If the vehicle is eguipped with navigation/CCC, it is also possible to make a fine adjustment via the CID (Central Information Display) in the submenu Air distribution. Compared to manual selection, fine adjustment offers the additional possibility of further individualiza¬ tion of the air distribution. Airflow Control The airflow control is dependent on the following settings and con¬ trol actions: • Manual blower setting • Automatic blower and flap setting - The automatic blower and flap functions are activated when the AUTO button is pressed. • Dynamic pressure compensation - The air volume at the air inlet grills increases disproportionately with increasing road speed. This effect is compensated for by the opening angle of the fresh-air flap being reduced as speed increases (dynamic pressure compensation). The opening angle is regulated according to the programming. • Blower control - If necessary, the power management system will assign priority levels to reduce the blower output (via K- CAN). • Effect of terminal 50 - When the engine is being started (ter¬ minal 50 ON), the blower is switched OFF to reduce the load on the vehicle battery. Front Stratification Adjustment Thumbwheel The front adjustment thumbwheel is part of the DSC/DTC/Hazard switch cluster. The thumbwheel signal is wired directly to the IHKA control unit as an analog/varying voltage signal. The IHKA panel sends the specific position signal to the front mixing flap motor via the LIN bus. Rear Stratification Adjustment Thumbwheel The rear adjustment thumbwheels is located to the right of the rear center vent. The thumbwheel potentiometer signal is wired directly to the JBE control unit as an analog/varying voltage signal. The JBE converts this signal into a digital signal over the K-CAN to the IHKA control unit which then sends the specific position signal to the rear mixing flap motor via the LIN bus. Climate Control Workbook 101 102 Climate Control Workbook Sunlight Adaptation (solar sensor) How the solar sensor affects the IHKA regulation on the driver's side and on the front passenger side is not programmed separately. The following functions are modified when automatic mode is acti¬ vated (depending on the intensity of sunlight): • Blower output is increased or reduced • Desired temperature value is increased or reduced MAX Cooling The MAX button makes it possible for the user to select maximum cooling with just one press of a button at the IHKA controls. When the MAX button is pressed, all functions, including the defrost func¬ tion, are deactivated. The air conditioning function is activated (if it was not already activated) and defined settings are selected, (example: temperature control is deactivated, ventilation flaps are fully opened). Residual Heat (REST) The residual-heat function allows the heat from the engine to be used to heat up the vehicle interior when the engine is not running (e.g. during a stop at a level crossing). The residual-heat function is only possible for a certain run-down peri¬ od (15 minutes from terminal 15 OFF). The DME is signaled to acti¬ vate the electric water pump via the bus system to circulate the coolant. Switch-on Conditions: • Terminal 15 OFF And • Run-down period active (up to 15 minutes after terminal 15 OFF) And • REST button in IHKA controls ON And • Ambient temperature below 25°C And • Engine temperature at some point above 60°C And • On-board supply voltage over 11.4 volts Conditions for Switching Off: • Terminal 15 ON Or • Residual heat ON (15 minutes) expired Or • REST button in IHKA control panel OFF Or • OFF condition activated with residual heat active (terminal R) Or • Prompt from power management to switch off auxiliary consumers Or • On-board supply voltage less than 11 volts Defrost Function When the defrost function is activated, the defroster flap (on the inside in front of the windshield) is opened fully. The fresh-air/air-re¬ circulation flaps move to the fresh air position. All other flaps are closed. The blower is run up to maximum output. AUTO Function When this button is pressed, all IHKA functions are set to automat¬ ic mode. If one or more automatically controlled functions are man¬ ually set, automatic control for the functions concerned will be can¬ celled. Note: All other functions remain automatically controlled. Heated Rear Window The heated rear window is switched on when the button in the IHKA control panel is pressed. The function indicator lamp in the button lights up. The heated rear window is switched off by pressing the button again or automatically after the heating time has expired. Defrosting Phase (1st heating period) When terminal 15 is switched ON, the first time the system is switched on, the time span for the heated rear window is defined as follows: • Ambient temperature down to -15°C: Heating period: 10 minutes • Ambient temperature below 15°C: Heating period: 17 minute Pulsing After the defrosting phase, the heating phase (25 minutes with pulsed heat output (on-off cycle: 40 seconds ON, 80 seconds OFF). The function indicator lamp in the button is off during puls¬ ing. reversed step-by-step in reverse order. 2nd Heating Period After the 1 st heating period has expired, each subsequent time the button is pressed will cause the heated rear window to be switched on for a further 30 minutes (defrosting phase).Afterthe 2nd heating period has expired, output is again pulsed. OFF The IHKA control panel is switched off when the blower speed is set to 0. (The control panel/control unit continues to run in the background.) Air-recirculation Mode In air-recirculation mode, the flow of outside air can be stopped to prevent pollution from entering the vehicle, e.g. in traffic conges¬ tion. Air inside the vehicle is continually re-circulated. To make sure that there is a sufficient supply of fresh air, air-recircu¬ lation mode is only available for a limited time. (30 minutes air recir¬ culation -> 30 seconds partial fresh air -> 30 minutes air recircula¬ tion -> etc.) Climate Control Workbook 103 104 Climate Control Workbook Automatic Air-recirculation Control If the AUC II sensor detects an increased level of pollutants in the environment from spark-ignition and diesel engines, the IHKA con¬ trol unit will automatically switch to air recirculation mode. To make sure there is still an adequate supply of fresh air, air recir¬ culation is only available for a limited time: • At ambient temperatures less than 0°C: 2 minute re-circulated air mode -> 20 seconds fresh air mode -> 2 minute re-circu- lated air mode -> etc. • At ambient temperatures from 0°C to 6°C: 3 minute re-circu¬ lated air mode -> 20 seconds fresh air mode -> 3 minute re¬ circulated air mode -> etc. • Operation without a/c function at ambient temperatures greater than 6°C: 4 minute re-circulated air mode -> 20 sec¬ onds fresh air mode -> 4 minute re-circulated air mode -> etc. • Operation with a/c function at ambient temperatures greater than 6°C: 12 minute re-circulated air mode -> 20 seconds fresh air mode -> 12 minute re-circulated air mode -> etc. When the engine is started and the AUC function activated, fresh- air mode is always selected for about. 40 seconds due to the warming phase of the AUC sensor. Condensation Sensor Program The following conditions must be satisfied for the condensation sensor to operate: • The engine must be running • The IHKA must be in automatic mode The IHKA control unit evaluates the condensation sensor signal (humidity). If condensation on the windshield is imminent, the fol¬ lowing measures are initiated in sequence to prevent condensation from forming: • Open defrost flaps further • Switch from air-recirculation/AUC/automatic air-recirculation mode to partial fresh-air mode • Switch from partially fresh air in air-recirculation/AUC/automatic air-recirculation mode to fresh air • Increase blower air volume • Reduce air volume for the footwell • Increase desired temperature value If one measure proves to be ineffective, the next measure is initiat¬ ed. Once successful, the measures previously performed are reversed step-by-step in reverse order. Convertible Mode (E93) The E93 Convertible with its retractable hardtop combines two vehicles in one. It is a Coupe when closed and a Convertible when open, a fact taken into account by the automatic climate control to create pleasant and comfortable heating/ventilation conditions. This characteristic makes it possible for an individual climate con¬ trol program for both states. The software automatically initiates the automatic climate control program when it detects that the hardtop is down. Trials and customer surveys have shown that the previous air con¬ ditioning systems set up for Sedans or Coupes were not ideal for a Convertible with the top down. The temperature and blower output stage had to be constantly readjusted for the purpose of ensuring pleasant interior conditions. All control parameters are adapted to the requirements of driving with the top down when the hardtop is lowered. Convertible mode requires no additional sensors. The IHKA con¬ trol unit was programmed with corresponding software that takes these specific parameters into account. Convertible mode is activated by opening the retractable hardtop. The IHKA receives the corresponding information on the status of the hardtop from the Convertible top module (CTM). Note: The E64 was also equipped with a convertible mode for the Climate Control. Convertible mode is always active on vehicles with no central infor¬ mation display (CID). On vehicles with central information display, the Convertible Mode box in the "Automatic Program" menu must first be activated. This activation is possibly only with the hardtop open and is set to active as part of initial programming. < X Automatic programs ► ■*> □ soft ZV medium □ intensive |CV Convertible A Radio mode switched on E93 CID Climate Program selection screen Note: If Convertible mode is not activated, the selected automatic program (soft, medium, intensive) is activated when the hardtop is opened. Climate Control Workbook 105 106 Climate Control Workbook Condition Based Service Fresh Air/Recirculating Air Filters The E9X is equipped with a carbon activated microfilter which is accessible from the engine compartment. i) 1. E90 Microfilter Fresh air is drawn in via two filter elements in the intake area in front of the bulkhead. The recirculated air is drawn in at the side by the blower via separate recirculating air filters. Fresh Air Filtering A particulate filter or a micro/activated charcoal "combination filter" is also used on the E70 fresh air intake. The particulate filter (also referred to as a microfilter) removes dust, pollen, soot and other dirt from the fresh air that is needed to control the climate of the vehi¬ cle. The adsorption filter (activated charcoal filter) has the job of remov¬ ing the pollutants (hydrocarbons, acidic gasses) that mainly occur in high concentrations under smog conditions from the fresh air used the vehicle’s IHKA system. Recirculated Air Filtering A new type of honeycomb filter is used in the recirculated air intake. The versions for fresh air particulate filters can also be used for fil¬ tering recirculated air, but are used for cleaning the air in the pas¬ senger compartment. Filter types and equipment in the E70. All filters are electrostatically charged during manufacture and have the characteristic of attract¬ ing particles and holding them in, therefore cleaning the air. The performance figures of an adsorption filter are initial pressure loss, particle separation, dust storage capacity, gas adsorption (such as n-butanes, sulphur dioxide, toluene) and are independent of the filter surface and the air-mass flow. In order to be able to cope with customer specific filter usage and associated change interval increases and reductions, the filter change intervals of the E70 have not been stored in the CBS (Condition Based Service) system. Note: The filter change intervals can be found in the relevant service literature. E70 Air Filtering Index Explanation Index Explanation 1 IHKA fresh air intake 3 IHKA recirculated air intake 2 IHKA fresh air filter 4 IHKA recirculated air filter Climate Control Workbook 107