TABLE OF CONTENTS Subject Page M62TU Engine. 2 Vanos Operation.3-12 Engine Cooling System. 13 IHKA System Auxilary Pump. 14 DME-ME 7.2 Engine Management. 15 IPO ME 7.2. 16 Integral Electronic Throttle System (EML).17 Input Signal/Components.19 Camshaft Position Sensors. 19 Hot Film Air Mass Sensor (HFM 5).20 Integrated Ambient Barometeric Pressure Sensor..21 Radiator Outlet Temperature Sensor..22 DSC III Road Speed Signal.22 Accelerator Pedal Sensor (PWG).23 EDK Throttle Position Feedback Signal.24 MFL Cruise Control Data Signal.25 Brake Light Switch.25 Can Bus.26 Output Control Functions.27 E-Box.27 Secondary Air Injection.28 Auxiliary Fan Control.29 Electric Throttle Control. 30 DM-TL.31 Leak Diagnosis Test Precondition 34 M62TU Engine / ME7.2 The 4.4i X5 is equipped with the M62 TU B44 (4.4 liter) engine. Features of the M62 TU engine include: • Digital motor Electronics Control ME 7.2. • Variable positioned intake camshaft VANOS system. • “EML” Electronic Throttle Control System identified as EDK. • Compact water cooled generator (F-alternator). • Thermostat controlled transmission fluid/engine coolant heat exchanger system for automatic transmission equipped vehicles. • Non Return Fuel Rail (Running Loss Compliance). • IHKA Auxiliary Water Pump. 2 M62 TU VANOS OVERVIEW The variable intake valve timing system on the M62 TU continues to be identified as VANOS. This acronym comes from the German words; VAriable NOckenwellen Steuerung, which means Variable Camshaft Control. The M62 TU VANOS system is a new variant providing stepless VANOS functionality on each intake camshaft. The system is continuously variable within its range of adjustment providing optimized camshaft positioning for all engine operating conditions. While the engine is running, both intake camshafts are continuously adjusted to their optimum posi¬ tions. This enhances engine per¬ formance and reduces tailpipe emissions. Both camshafts are adjusted simultaneously within 20° (maxi¬ mum) of the camshafts rotational axis. This equates to a maximum span of 40° crankshaft rotation. The camshaft spread angles for both banks are as follows. t 12 mm 10 5mm 8 mm 6 mm 4 urn 2mm -j LU -~r i 104 - _ u "S j / > z _ V HA AL) UST ,/E j r J V r j * i 124 _■■_L 3 4 1= J I r i—i—r—i—i—i—r—r 9. t DEFAULT - RETARD ^>1 I I M I M MAXIMUM - ADVANCE ij.l._ INTAKE VALVE I IT 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640 680 720 m- OPEN DURATION 228' ' OPEN DURATION 236’ CRANKSHAFT ROTATION 3 VANOS BENEFITS The design of a camshaft for a non adjustable valve timing system is limited to the required overall performance of the engine. • An intake camshaft with an advanced (early) profile will provide a higher performing power curve at a lower engine speed. But at idle speed the the advanced position will create a large area of intake/exhaust overlap that causes a rough, unstable idle. • On the other hand, an intake camshaft with a retarded (late) profile will provide a very smooth, stable idle but will lack the cylinder filling dynamics needed for performance characteristics at mid range engine speeds. The ability to adjust the valve timing improves the engines power dynamics and reduces tailpipe emissions by optimizing the camshaft angle for all ranges of engine operation. VANOS provides the following benefits: • Increased torque at lower to mid range engine speeds without a loss of power in the upper range engine speeds. • Increased fuel economy due to optimized valve timing angles. • Reduction of exhaust emissions due to optimized valve overlap. • Smoother idle quality due to optimized valve overlap. 4 BASIC FUNCTION OF BMW VANOS SYSTEMS All BMW VANOS systems are operated through electric/hydraulic/mechanical control. VANOS IN DEFAULT POSITION fRETARDE MECHANICAL CONTROL ELECTRIC CONTROL £JHfMbi£ HYDRAULIC CONTROL VANOS IN FULL MECHANICAL a CONTROL y POSITION ELECTRIC CONTROL sitiivi £NS 1 ^ u ' FI" 1 ■j N P-t-'i 1 . n ^ ■ r 1 ,|"| |,vi| m’i h W u ? TTZTi i_j M62 TU VANOS COMPONENTS PRIMARY SPROCKET VANOS TRANSMISSION SECONDARY SPROCKET M62 TU VANOS components include the following for each cylinder bank: • New cylinder heads with oil ports for VANOS • VANOS transmission with sprockets • Oil distribution flange • PWM controlled solenoid valve • Oil check valve • Camshaft position impulse OIL DISTRIBUTION CLCCTFIEAL TIN OOriT^CTC V FOR DE“ECTI N G MAX RETAR D RIFTu M FOfi “1C Til h, G VANOS TRANSMISSION WITH SPROCKETS INTAKE CAMSHAFT INTAKE CAMSHAFT OIL PORTS (Left Hand Threads) CHECK 1 EXHAUSTCAMSHAFT VALVE IMPULSE WHEEL CONTROL SOLENOID EXHAUST CAMSHAFT SPROCKET BOLT (Left HandTh reads) VANOS CONTROL SOLENOID & CHECK VALVE: The VANOS solenoid is a two wire, pulse width modulated, oil pressure control valve. The valve has four ports; 1. Input Supply Port - Engine Oil Pressure 2. Output Retard Port - To rear of piston/helical gear (retarded camshaft position) 3. Output Advance Port - To front of piston/helical gear (advanced camshaft position) 4. Vent - Released oil pressure A check valve is positioned forward of the solenoid in the cylinder head oil gallery. The check valve maintains an oil supply in the VANOS transmission and oil circuits after the engine is turned off. This prevents the possibility of piston movement (noise) within the VANOS transmission system on the next engine start. 7 VANOS TRANSMISSION: The primary and secondary timing chain sprockets are inte grated with the VANOS transmission. The transmission is a self contained unit. The controlled adjustment of the camshaft occurs inside the “transmis¬ sion”. Similar in principle to the six cylinder engine VANOS systems, con¬ trolled oil pressure moves the piston axially. The helical gear cut of the piston acts on the helical gears on the inside sur¬ face of the transmission and rotates the camshaft to the specific advanced or retarded angle position. Three electrical pin contacts are locat¬ ed on the front surface to verify the default maximum retard position using an ohmmeter. This is required during assembly and adjustment, (see service notes further on). HELICAl 6 EAR INTAKE CAMSHAfT Camshaft POSITION 5EN50H i H ETA ItO OIL ClfitUlT ADVANCE OH circuit ■_ j VAifOS SOLENOID ENGINE OIL PUMP PRESSURE OIL DISTRIBUTION FLANGES: The oil distribution flanges are bolted to the front surface of each cylinder head. They provide a mounting location for the VANOS solenoids as well as the advance-retard oil ports from the solenoids to the intake camshafts. CAMSHAFTS: Each intake camshaft has two oil ports separated by three sealing rings on their forward ends. The ports direct pressurized oil from the oil distribution flange to the inner workings of the VANOS transmission. Each camshaft has REVERSE threaded bores in their centers for the attachment of the timing chain sprockets on the exhaust cams and the VANOS transmissions for each intake camshaft as shown. RETARD '‘OIL PORTS 1 ' ADVANCE rD\ REVERSE THREADED BORE \ l } l SEALING RINGS CAMSHAFT POSITION IMPULSE WHEELS: The camshaft position impulse wheels pro¬ vide camshaft position status to the engine control module via the camshaft position sen¬ sors. The asymmetrical placement of the sensor wheel pulse plates provides the engine control module with cylinder specific position ID in conjunction with crankshaft position. 8 M62 TU VANOS CONTROL As the engine camshafts are rotated by the primary and secondary timing chains, the ME7.2 control module activates the VANOS solenoids via a PWM (pulse width modulated) ground signal based on a program map. The program is influenced by engine speed, load, and engine temperature. • Shown below: In its inactive or default position, the valves direct 100% engine oil pres¬ sure flow to achieve max “retard” VANOS positioning POSITION • Top of next page: As the Pulse Width Modulation (PWM) increases on the control sig¬ nal, the valve progressively opens the advance oil port and proportionately closes the retarded oil port. Oil pressure pushes the piston toward the advance position. Simultaneously the oil pressure on the retarded side (rear) of the piston is decreased and directed to the vent port in the solenoid valve and drains into the cylinder head. • Bottom of next page: At maximum PWM control, 100% oil flow is directed to the front surface of the piston pushing it rearward to maximum advance. Varying the pulse width (on time) of the solenoids control signals proportionately regulates the oil pressures on each side of the pistons to achieve the desired VANOS advance angle. 9 imm} jig* i+w a ADVANCE POSITION w bM 1 ^ .■ f T _ MM j . ■ , — rvu, __ .. , _ t ‘■ 7 71 , r~ " ii □ 33 r. ,i_ 1 .■ VANOS SERVICE NOTES VALVE TIMING PROCEDURES Refer to TI5 for complete Valve Timing Procedures. M62 TU valve tinning adjustment is sim¬ ilar to the previous non VANOS M62 engine with the exception of setting the VANOS transmissions to their max retard positions with an ohmmeter and attaching the camshaft gears to each camshaft with single reverse threaded bolts. • After locking the crankshaft at TDC, the camshaft alignment tools (P/N 90 88 6 112 440) are placed on the square blocks on the rear of the camshafts locking them in place. • The exhaust camshaft sprockets and VANOS transmission units with timing chains are placed onto their respective camshafts. • The exhaust camshaft sprockets and VANOS transmissions are secured to the camshafts with their respective single, reverse threaded bolt. Finger tighten only at this point. Install the chain tensioner into the timing chain case and tension the chain. • Connect an ohmmeter across two of the three pin contacts on the front edge of one of the VANOS transmissions. Twist the inner hub of transmission to the left (counter clock¬ wise). Make sure the ohmmeter indicates closed circuit. This verifies that the trans¬ mission in the default max retard position. • Using an open end wrench on the camshaft to hold it in place, torque the VANOS trans¬ mission center bolt to specification. CAMSHAFT IMPULSE WHEEL POSITION TOOLS The camshaft impulse wheels require a special tool set to position them correctly prior to torquing the retaining nuts. The impulse wheels are identical for each cylinder bank. The alignment hole in each wheel must align with the tool’s alignment pin. Therefore the tools are different and must be used specifically for their bank. The tool rests on the upper edge of the cylinder head and is held in place by the timing case bolts. Refer to the TIS repair manual section for complete information. VANOS SOLENOID REPLACEMENT Refer to TIS repair manual section for com¬ plete solenoid replacement procedures. The solenoids are threaded into the oil distri¬ bution flanges through a small opening in the upper timing case covers. Special Tool 11 6 420 is required. VANOS TRANSMISSION RETARD POSI¬ TION SET UP TOOLS Special Tool 11 6 440 is used to rotate the transmission to the full retard position when checking the piston position with an ohmme- ter. This tool engages the inner hub of the trans¬ mission provides an easy method of twisting it to the left for the ohmmeter test. Refer to SI Bulletin 04 12 98 for additional special tool information. DIAGNOSIS The VANOS is fully compatible with the diagnostic software providing specific fault codes and test modules. Additionally, diagnostic requests section provides status of the PWM of the VANOS solenoids and camshaft position feedback via the camshaft position sensors. The Service Functions section of the DIS/MoDiC also provides a VANOS system test. 12 ENGINE COOLING SYSTEM The cooling system concepts introduced in the 1999 Model year including the automatic transmission heat exchanger and the the water cooled alternator have been retained for the X5. The component locations have however been changed: • Thermostat for heat exchanger mounted directly on radiator • Transmission heat exchanger - right side of radiator. 13 IHKA SYSTEM AUXILIARY PUMP The auxiliary water pump for the IHKA is mounted on the left side of the radiator. The func¬ tion of the pump remains the same as follows: provide adequate coolant tion. provide coolant circulation of IHKA. flow for IHKA opera¬ tor the REST function 14 DME-ME 7.2 ENGINE MANAGEMENT SYSTEM The “ME” designation identifies the system as “M” = Motronic, “E” = EML. ME 7.2 LOCATION IN E-BOX SKE BREAKOUT BOX SET P/N 90 88 6 121 300 Manufactured by Bosch to BMW specifica¬ tions 134 pin SKE (standard shell construction) con¬ trol module located in E box Diagnostic communication protocol-KWP2000 Uses break-out box set (P/N 90 88 6 121 300) Integral EML throttle control system - monitors an interior installed PWG - actuates an electric throttle valve (EDK) Integral Cruise control functionality - monitors cruise control requests - monitors brake pedal and clutch switches - carries out throttle control directly via EDK Carries out DSC III torque reduction requests. VANOS control Integrated altitude sensor Integrated temp sensor for monitoring E box temperatures Control of E-box fan One touch engine start control Oxygen Sensor heating Engine overrev & Max speed limitation Active Hall sensor for camshaft position monitoring Single speed secondary air injection system Electrically heated coolant system thermostat Longlife spark plugs IHKA Auxiliary Fan control DM-TL (Diagnostic Module - Tank Leak Diagnosis System) ENGINE CONTROL MODULE HARNESS 26 PIN BOX 88 88 6 611 459 88 88 6 611 459 1 2 3 4 5 (9 pins) (24 pins) (52 pins) (40 pins) (9 pins) 15 INTEGRAL ELECTRIC THROTTLE SYSTEM (EML) FUNCTIONAL DESCRIPTION When the accelerator pedal is moved, the PWG pro¬ vides a change in the mon¬ itored signals. The ME 7.2 compares the input signal to a programmed map and appropriately activates the EDK motor via proportional¬ ly high/low switching cir¬ cuits. The control module self-checks it’s activation of the EDK motor via the EDK feedback potentiometers. Requirements placed on the Electric Throttle System: • Regulate the calculated intake air load based on PWG input signals and programmed mapping. • Control idle air when LL detected with regard to road speed as per previous systems. • Monitor the driver’s input request for cruise control operation. • Automatically position the EDK for accurate cruise control (FGR) operation. • Perform all DSC III throttle control interventions. • Monitor and carryout max engine and road speed cutout. 17 PWG SIGNAL MONITORING & PWG FAILSAFE OPERATION: • As a redundant safety feature the PWG provides two separate signals from two integral potentiometers (Pot 1 and Pot 2) representing the driver’s request for throttle activation. • If the monitored PWG potentiometer signals are not plausible, ME 7.2 will only use the lower of the two signals as the driver’s pedal request input providing failsafe operation. Throttle response will be slower and maximum throttle position will be reduced. • When in PWG failsafe operation, ME 7.2 sets the EDK throttle plate and injection time to idle (LL) whenever the brake pedal is depressed. • When the system is in PWG failsafe operation, the instrument cluster matrix display will post “Engine Emergency Program” and PWG specific fault(s) will be stored in memory. EDK FEEDBACK SIGNAL MONITORING & EDK FAILSAFE OPERATION: • The EDK provides two separate signals from two integral potentiometers (Pot 1 and Pot 2) representing the exact position of the throttle plate. • EDK Pot 1 provides the primary throttle plate position feedback. As a redundant safe¬ ty feature, Pot 2 is continuously cross checked with Pot 1 for signal plausibility. • If plausibility errors are detected between Pot 1 and Pot 2, ME 7.2 will calculate the inducted engine air mass (from HFM signal) and only utilize the potentiometer signal that closely matches the detected intake air mass. - The ME 7.2 uses the air mass signalling as a “virtual potentiometer” (pot 3) for a comparative source to provide failsafe operation. - If ME 7.2 cannot calculate a plausible conclusion from the monitored pots (1 or 2 and virtual 3) the EDK motor is switched off and fuel injection cut out is activated (no failsafe operation possible). • The EDK is continuously monitored during all phases of engine operation. It is also briefly activated when KL 15 is initially switched on as a “pre-flight check” to verify it’s mechanical integrity (no binding, appropriate return spring tension, etc). This is accom¬ plished by monitoring both the motor control amperage and the reaction speed of the EDK feedback potentiometers. If faults are detected the EDK motor is switched off and fuel injection cut off is activated (no failsafe operation possible). The engine does how¬ ever continue to run extremely rough at idle speed. • When a replacement EDK is installed, the ME 7.2 adapts to the new component (required amperage draw for motor control, feedback pot tolerance differences, etc). This occurs immediately after the next cycle of KL 15 for approximately 30 seconds. During this period of adaptation, the maximum opening of the throttle plate is 25%. 18 INPUT SIGNALS/COMPONENTS CAMSHAFT POSITION SENSORS Located on the upper tinning case covers, the camshaft position sensors monitor the posi¬ tion of the camshafts to establish start of ignition firing order, set up sequential fuel injection triggering and for accurate camshaft advance-retard (VANOS) timing feedback. Each intake camshaft’s advance-retard angles are adjusted simultaneously yet indepen¬ dently. For this reason ME 7.2 requires a camshaft position sensor on each cylinder bank for accurate feedback to monitor the VANOS controlled camshaft positioning. The sensors are provided with operating power from the ECM main relay. The sensors pro¬ duce a unique asymmetrical square-wave signal representative of the impulse wheel shape. The sensors are new in the fact that they are “active” hall effect sensors. Active hall sen¬ sors provide: • low signal when a tooth of the camshaft impulse wheel is located in front of the sensor • high signal when an air gap is present. The active hall sensors supply a signal representative of camshaft position even before the engine is running. The ME 7.2 determines an approximate location of the camshafts posi¬ tions prior to engine start up optimizing cold start injection (reduced emissions.) 19 HOT FILM AIR MASS SENSOR (HFM 5) The M62 TU is equipped with a new Hot Film Air Mass Sensor identified as HFM 5. It is a combined air mass/intake air temperature sensor. The separate intake air temperature sensor is no longer used on the M62 TU. The HFM 5 is provided with operating power from the ECM main relay. Based on calcu¬ lated intake air mass, the HFM 5 generates a varying voltage between 0.5 and 4.5 volts as an input signal to the ME 7.2 An additional improvement of the HFM 5 is that the hot film element is not openly suspended in the center bore of the sensor as with previous HFMs. It is shrouded by a round fronted plastic labyrinth which isolates it from intake air charge pulsations. This feature allows the HFM to monitor and calculate the intake air volume with more accuracy. This feature adds further correction for calculating fuel injection “on” time (ti) which reduces emissions further. 20 INTEGRATED AMBIENT BAROMETRIC PRESSURE SENSOR The ME 7.2 Control Module contains an integral ambient barometric pressure sensor. The sensor is part of the SKE and is not serviceable. The internal sensor is supplied with 5 volts. In return it provides a linear voltage of approx. 2.4 to 4.5 volts representative of barometric pressure (altitude). The ME 7.2 monitors barometric pressure for the following reasons: • The barometric pressure signal along with calculated air mass provides an additional correction factor to further refine injection “on” time. • Provides a base value to calculate the air mass being injected into the exhaust system by the secondary air injection system. This correction factor alters the secondary air injection “on” time, optimizing the necessary air flow into the exhaust system. • Recognition of altitude above the accepted cri¬ teria postponing DM-TL activation for evapora¬ tive emission leak diag¬ nosis. ©/■- © FUEL INJECTION __ ON TIME 4 ? 4 A SECONDARY AIR PUMP RELAY VACUUM VENT VALVE I IM 0 SENSOR HEATING Y+wffl mm wiwim YriYf LEAK DIAGNOSISTEST POSTPONEMENT 21 RADIATOR OUTLET TEMP SENSOR First seen on the MS 42.0 control system, the ME 7.2 uses an additional water temperature sensor located on the radiator outlet. ME 7.2 requires this signal to monitor the water temperature leaving the radiator for precise acti¬ vation of the IHKA auxiliary fan. DSC III - ROAD SPEED SIGNAL ME 7.2 receives the road speed signal directly from the DSC III control module for maximum vehicle speed management. The DSC control module provides a processed output of the right rear wheel speed sensor as a digital square wave signal. The frequency of the signal is proportion¬ al to the speed of the vehicle (48 pulses per one revolution of the wheel). RADIATOR OUTLET TEMPERATURE SENSOR The cruise control function (FGR) of the ME 7.2 also monitors vehicle speed from the redun¬ dant vehicle speed CAN bus signal. The CAN bus speed signal is provided by the DSC III control module and based on the combined average of both front wheel speed signals. Additionally, ME 7.2 monitors all four wheel speed signals via CAN bus signalling to detect abrupt fluctuations in vehicle speed signals for the purpose of detecting rough road sur¬ faces. This is continuously monitored as part of the OBD II emission requirements provid¬ ing a correction factor for misfire detection plausibility. Earlier systems only monitored the right rear speed signal input from DSC. nJLTLTL LEFT FRONT fUlTlTL rirLnnL^ . RIGHT ^ FRONT ,.(§ muin. i PROCESSED RIGHT REAR WHEEL SPEED c© © L 1 a ro CO m □ N> OI 1 - 1 - © 22 ACCELERATOR PEDAL SENSOR (PWG) The driver's application of the accelerator pedal is monitored by a PWG sensor in the dri¬ ver's footwell as with previous non-bowden cable EML systems. The PWG provides two separate variable voltage signals to the ME 7.2 control module for determining the request for operating the Electric Throttle Valve (EDK) as well as providing a kickdown request with automatic transmission vehicles. ME 7.2 @r>- The ME 7.2 monitors the changing signal ranges of both circuits as the pedal is pressed from LL to VL. ? -3N* L vciTtc-r wthinthe nea zone* nohuuhile 3.EV THROTTLE PE ML POSITION