Table of Contents Subject Page Central Body Electronics (ZKE IV) .2 Objectives of the Module .2 Purpose of the System.3 System Components .4 Power Distribution .5 Windshield Wiping/Washing. 6 318ti Rear Window Wiping/Washing.8 Central Locking .9 Door Lock Heating.19 Power Windows/Sunroof .20 Sunroof.23 Interior Lighting .25 General Functions .27 Consumer Cut Off/Overload Proteotion.27 Review Questions 28 CENTRAL BODY ELECTRONICS (ZKE IV) Models: E36 and Z3 Production Date: E36 1994 MY (including 318ti) to End of Production Z3 Coupe, Roadster (including M) 1997 MY to Present Manufacturer: Hella Pin Connectors: 6 - Black 18 pin, Black 15 pin. Yellow 26 pin. Green 26 pin. Natural 26 pin. White 15 pin Objectives of the Module After completing this module, you will be able to: • List the funotions direotly oontrolled by the GM IV. • Desoribe how the GM IV reoognizes the key position from the driver’s door. • Explain the “Gomfort Glosing” feature. • Understand the differenoe between “single” and “double” look. • Desoribe Windshield Wiper Blooking Proteotion. • Explain how EWS affeots the Gentral Looking System. 2 Central Body Electronics ZKE IV Central Body Electronics (ZKE IV) Purpose of the System The Central Body Electronics (ZKE IV) system manages the following functions: GM IV (1. in Diagram) • Interior Lighting • Centrai Locking • Door Lock Heating • Power Windows/Sunroof • Consumer Cut Off/Overioad • Diagnosis Washer/Wiper Module (2. in Diagram) Windshield Wiping/Washing E36 Viewed with Glovebox Removed Relay Module (3. in Diagram) • Power Windows (rear doors - on 4 door and Convertibie only) Convertible Top Module • Power Window Interface • Top Comfort Close • Trunk Lockout when top is in operation The ZKE IV system was introduced on the E36 Convertible and is also used in the Z3. Most of the functions operate the same on these vehicles with minor changes and added fea¬ tures to the system. ZKE IV is the fourth generation of central body control systems. The GM IV is responsible for controlling most of the Body Electronic Functions from one central module. 3 Central Body Electronics ZKE IV System Components General Module (GM IV): The GM is a micro¬ computer that is the central component (heart) of the Central Body Electronics. The GM is loc¬ ated behind the glove box. The main objectives for using the GM are: • Increase Overall Reliability • Centralize Electronic Systems • Decrease Assembly and Service Repairs • Centralized Diagnosis of all ZKE Components • Individualization of Features (Coding) The GM requires input data to perform Central Body Electronics functions. The inputs are sup¬ plied by digital switched signals such as: • Driver’s Door Lock Microswitch: supplies vol¬ tage (KL 30) to the GM when switched. A path to ground is provided by the GM (inter¬ nally). The GM monitors the input voltage. • Centrai Lock Button (E36 from 96 MY): sup¬ plies a ground circuit to the GM when switc¬ hed. The GM supplies and monitors a refer¬ ence voltage (5v) that is “pulled” low when the switched ground path is provided. Driver’s Door Lock Microswitch ,,, .. Signal Monitor 12520101.eps The GM processes the input information and contains “coded” instructions that allow a spe¬ cific output control of functions. The GM will produce output controls using int¬ ernal transistors to switch relays allowing cur¬ rent flow (providing voltage or ground) through circuits and actuators. Actuators ( such as relays and motors) are used by the GM to oper¬ ate or control various output functions. 4 Central Body Electronics ZKE IV Power Distribution The power distribution box whioh inoludes the fuses for the E36 and Z3 is looated in the engine oompartment. A fuse designation label is also looated on the inside lid of the fusebox. The label notes: • Fuse rating in amps • Looation • Cirouit listing by fuse ABS RELAYS HORN ER RELAY FUEL PUMP RELAY LOWBEAM FOGLIGHT E36 Shown ENGINE MAIN HAZARD RELAY (< 97) FLASHER Looated under and to the left of the steering oolumn is: • Cheek Control Module • Common oonneetor plates (splioe box) • Window/Sunroof Relay • Crash Alarm Relay CHECK CONTROL MODULE RELAY CARRIER CRASH ALARM RELAY (>94 Model year) ' # 5 Central Body Electronics ZKE IV Windshield Wiping/Washing Purpose of the System The windshield wiping/washing functions are controlled by a separate wiper module (WWM). The system has never been directly controlled by the ZKE, even though it is a body eleotrioal system. The system has four wiping stages inoluding one interval wip¬ ing speed when the ignition is in position KL R or KL15. The wiper motor output oontrol is by the WWM boated behind the glovebox. System Components E 36 Wiper stalk - with Principle of Operation Wiper Stalk Switch Input The wiping stage inputs are through a ooded oombination switoh that supplies a ground signal to the WWM. The wiping stages inolude: Single (S): Momentarily holding the wiper switoh down in the single position provides a momentary ground signal to aotivate a single sweep in slow speed. Slow (I) and Fast (II): The stage I and stage II wiping speeds are road speed dependent. Stage I switohes to intermittent when the vehiole is stopped and stage II switohes to stage I when stopped. Windshield Washing: The wash request provides a switohed ground input to the WWM by pulling the stalk rearward. The WWM aotivates the windshield washer pump direotly. When the washing funotion is aotivated, the pump runs as long as the switoh is held. The wipers switoh on and will oontinue to for 3 wiping oyoles after the switoh is released. Intermittent: The interval time of the wipers is vehiole speed dependent. As the vehiole speed inoreases, wiping interval times deorease. This timed interval is set in the oontrol module and is not programmable. The programmed intermittent oyoles are as follows: 0-10 mph 10-25 mph 25-50 mph 50-69 mph 69-93 mph >93 mph 14 sec’s 8 sec’s 7 sec’s 6 sec’s 5 sec’s 4 sec’s 6 Central Body Electronics ZKE IV Blocking Protection The wiper module receives a feedback signal from fhe wiper mofor when the wipers are switched on. If this feedback signal is missing for several seconds after the wipers are switched on, the module will switch the motor off. The wiper switch must be moved to the off position before another attempt can be made to turn the wipers on. If this blocking protection has activated several times, the ignition must be cycled before the wipers can be switched on again. The wiper module is not connected to the diagnostic link for troubleshooting purposes. Standard troubleshooting procedures using an ETM and DISplus multimeter must be employed to diagnose the wiper/washer. System Components: Inputs - Processing - Outputs SPEED SIGNAL "A" Switch Logic 1 2 3 Single Wipe H H L Intermittent Wipe H L H Slow Wipe (Stage 1) H H L Fast Wipe (Stage II) L H L 7 Central Body Electronics ZKE IV 318ti Rear Window Wiper/Washer The rear glass of the 318ti has a wiper/washer. This system has an additional set of oon- taots in the wiper stalk switoh that operates the rear window system as well as front win¬ dow wiper/washer system. Operation is as follows: • Intermittent Wiping: Push the wiper switoh away from the steering wheel briefly to aoti- vate intermittent wipe. Pressing a seoond time will switoh the wiping off. • Wash/Wipe: Push the lever away from the steering wheel and hold, this will aotivate the washer pump and the wiper as long as the switoh is held. System Components: Inputs - Processing - Outputs 8 Central Body Electronics ZKE IV Central Locking Purpose of the System The Central Locking System provides locking/ unlocking of the entire vehicle from one central exterior point. From the driver’s door, passenger’s door or lug¬ gage compartment (>96 MY), a lock/unlock request will lock/unlock all exterior doors, lug¬ gage compartment and the fuel filler flap (and glove box E36iC only). Locking from the luggage compartment lock cylinder and leaving the lock cylinder in the hori¬ zontal position will manually lock the luggage compartment in the “valet” position. From inside, the vehicle can be locked using one of the front door lock knobs or a central locking button (>96 MY E36 which also unlocks the vehicle) located in the center console. The doors can be unlocked by pulling twice on the Interior door handle. Locking the vehicle from the central switch or door lock knob will “single lock” all doors, luggage compartment and not lock the fuel filler flap (or glovebox on the E36IC). The Central Locking System utilizes the GM IV to carry out all of the locking/unlocking fea¬ tures: • When locked from the outside, the vehicle will double lock and arm the alarm system (only if equipped with DWA, not the accessory Alpine Alarm). The ignition must be switched off and the driver’s door must be opened and closed. • The EWS II is interfaced for double lock monitoring and unlock function(>1/95 Production Date). With the presence of an accepted EWS II key and switching the ignition “on”, the GM IV will unlock the vehicle. • In the event of an accident (ignition must be switched on), the GM IV will be signalled to unlock all of the doors. Central Body Electronics ZKE < CD • Anti-theft drive away protection feature with double lock (>1/95 Production Date when locking the vehicle from the exterior). • Comfort closing of the windows is posible from both front door locks if held in the lock position. • 1996 E36 - Sunroof added to comfort closing feature. • E36iC - The trunk is locked out when the convertible top is in operation. Fully automatic convertible top added to comfort closing feature (97 MY and later vehicles). Hardware Features • The door lock buttons are mechanically uncoupled from the lock actuators when locked. The door lock buttons also “mechanically” lock the individual doors. This provides man¬ ual locking in the event of a central locking malfunction. • Child safety locks (located in the rear doors on a four door vehicle) are actuated by sliding a lever. The door can now only be opened from outside. • The luggage compartment can be manually locked with a “Master Key” and leaving the lock cylinder in the horizontal position which prevents opening by any other method (sec¬ ured for valet). • The Fuel Filler Flap mechanical release is found in the right side of the luggage compartment. • The glove box has a lock cylinder to secure the contents by manual locking with a “Master Key” and leaving the lock cyl¬ inder in the horizontal position which prevents opening by any other method (secured for valet). The valet key is not mechanically capable of entering either of these lock cylinders. 10 Central Body Electronics ZKE IV Central Locking - ZKE IV The locking and unlocking of the lock actuators is controlled from three relays in the GM. The door lock actuator “Pin Contacts” and lock micro-switches provide the inputs to the GM for locking/double locking and unlocking of the doors, trunk, fuel filler flap (and glove box on the E36iC only). The relays in the GM provide both power and ground depending on the direction of actuator movement (lock/unlock). System Components: Inputs - Processing - Outputs KL 30 RELAY# CENTRAL LOCK DOUBLE LOCK UNLOCK 1 HIGH HIGH LOW 2 LOW HIGH LOW 3 LOW LOW HIGH DOOR LOCK ACTUATORS {4X) CONVERTIBLE TOP STORAGE LID SWITCH GRAY COLORED COMPONENTS ARE FOR CONVERTIBLE MODELS ONLY 11 Central Body Electronics ZKE IV Lock Actuator Operation The lock actuators contain the electrical motor drive, the lock/ unlock switch contacts and the integral single/double lock lim¬ iting switch. The actuators control the mechanical locking/unlocking func¬ tion of the doors by sliding two protruding levers. The precise positioning of the levers provides the unlock, single lock and double lock positions of the latch mechanism. The electro-mechanical operation of all the lock positions are provided on the following pages: LOCK ACTUATOR LOCK LEVERS LATCH MECHANISM UNLOCKED-NEUTRAL POSITION UNLOCKED-NEUTRAL POSITION ZKEIV GENERAL MODULE AS OF 1-94 PRODUCTION THE DOUBLE LOCK ■KEY POSITION" WAS ELIMINATED. LOCKING FROM THE VEHICLE EXTERIOR PROVIDES A DOUBLE LOCK REQUEST o • All switch contacts are in their rest positions. • The lock actuator/latch mechanisms are in the unlocked position. • Raising the door handle or pulling the interior door latch will mechanically open the door. 12 Central Body Electronics ZKE IV Central Locking System Terminology “Single lock”, “Central lock”: Vehicle is locked via the lock knob, or the oonsole mounted oentral look button (>12-95 prod). “Double lock”, “Central arrest”: Vehiole has been looked from the exterior with the key at the driver’s door, passenger’s door or trunk. SINGLE LOCK - Phase 1, mechanical lock at door and lock signal generation SINGLE LOCK - Phase 1, mechanical lock at door and lock signal generation AS OF 1-94 PRODUCTION, THE DOUBLE LOCK "KEY POSITION" WAS ELIMINATED. LOCKING FROM THE VEHICLE EXTERIOR PROVIDES A DOUBLE LOCK REQUEST • The lock button and key mechanically rotate the lock lever which decouples the exterior door handle from the latch. • When rotated, the lock lever also slides an internal switch ramp to the left closing the lock microswitch. • This provides the lock signal to the GM (cont’d on next page.) 13 Central Body Electronics ZKE IV SINGLE LOCK - Phase 2, activation of actuators at all door locks When the GM receives the lock signal it activates internal relay #1, providing power through the closed single lock contact to the aotuator motor. Ground is provided through the mod¬ ule’s olosed oontaot of relay #3. All of the vehiole’s aotuator motors are energized until the single look oirouit is opened by the gear driven slider. The aotuators stop at the single looked position. At this point, the external door handles are deooupled from the latoh meohanism prevent¬ ing entry from outside of the vehiole. ZKE IV GENERAL MODULE AS OF 1-94 PRODUCTION, THE DOUBLE LOCK "KEY POSITION" WAS ELIMINATED. LOCKING FROM THE VEHICLE EXTERIOR PROVIDES A DOUBLE LOCK REQUEST If the internal door handle, the look buttons or the oentral look button on the oenter eon- sole are operated, the door returns to unloek meehanieally and ean be opened. 14 Central Body Electronics ZKE IV DOUBLE LOCK - Electrical Activation Turning the key from any outside look oylinder oauses the external double look mioro-switoh to olose. The GM reoognizes this high signal as a double look request. The GM aotivates internal relay #2, providing oontinued motor operating power through the olosed oontaots of the internal double look oirouit. Ground is provided through the GM’s internal relay # 3. The aotuator motors are energized until the internal double look oirouit is switohed baok to the single look oirouit by the gear driven slider. ZKEIV GENERAL MODULE AS OF 1 -94 PRODUCTION, THE DOUBLE LOCK "KEY POSITION" WAS ELIMINATED. LOCKING FROM THE VEHICLE EXTERIOR PROVIDES A DOUBLE LOCK REQUEST Notes: 15 Central Body Electronics ZKE IV DOUBLE LOCK - Mechanically Decoupled When the slider switches the circuit back to single lock it also pushes the double lock lever to the left until it stops. In this position, the double look lever deoouples the look button from the latoh meohanism. The look button oan be pulled but will not unlook the door sinoe it is not ooupled to the meohanism. Spring pressure pulls the button baok down when released. At this point, unlook is only possible when a key is turned to the unlook position from an outside door look or if the GM reoeives the unlook signal from the EWS II oontrol module. ZKEIV GENERAL MODULE MECHANICALLY DECOUPLED AS OF 1-94 PRODUCTION THE DOUBLE LOCK "KEY POSITION" WAS ELIMINATED. LOCKING FROM THE VEHICLE EXTERIOR PROVIDES A DOUBLE LOCK REQUEST o Notes: 16 Central Body Electronics ZKE IV UNLOCK FROM DOUBLE LOCK When the GM receives the unlock request from a key location it activates internal relay #3 providing operating power to the aotuator motor in the opposite direotion. The single and double look oirouits (internal relays 1 & 2) are not aotivated at all during the unlook funotion providing ground for the motor to bring the aotuator baok to the fully un- looked position. ^ KL30 RELAY #1 • m loQQpOrj i spS O J fl] , R z 2r r “1 M DOUBLE LOCK INPL ZKEIV GENERAL MODULE KL30 T ' ' A /!» / i i DOUBLE f-^LOCK ' ^ 'swrrcH \ AS OF 1 -94 PRODUCTION, THE DOUBLE LOCK "KEY POSITION" WAS ELIMINATED. LOCKING FROM THE VEHICLE E>CrERIOR PROVIDES A DOUBLE LOCK REQUEST Notes: 17 Central Body Electronics ZKE IV Locking Protection Power protection for the door locking circuit is provided by a “time monitored” activation of the door lock actuators by the GM. The door lock actuators are provided power for the duration of time needed to run the actuator to the desired position. • The maximum on time for the actuators is 0.7 seconds. Crash Signalling The Supplemental Restraint System control module provides a switched signal to the GM in the event of an accident. This signal was previously provided by the Crash Alarm locat¬ ed in the left front kick panel on earlier models (<97 MY). The signal is an output function of the control module and becomes active when the impact threshold has been exceeded. The GM unlocks the vehicle, switches on the interior lights and signals the Crash Alarm Relay to flash the exterior lights when this signal is active. 18 Central Body Electronics ZKE IV Door Lock Heating (optional) Purpose of the System The Driver’s door look cylinder is surrounded by a heating coil to warm the lock cylinder if in case it is frozen due to moisture and below freezing temperatures. Principle of Operation The GM controls the lock heater by providing voltage through a final stage transistor. The heater is switched on by raising the driver’s door handle. Prerequisites for heater operation include: • Vehicle locked • Door handle raised for approximately 3 seconds Power is applied to the heater for a maximum of 32 seconds. A timed arrest of 16 minutes is activated after 3 heating attempts. The door lock heater is switched off immediately after unlocking the door. System Components: Inputs - Processing - Outputs 19 Central Body Electronics ZKE IV Power Windows/Sunroof Purpose of the System The features of the power windows and sunroof system inolude: • One-fouoh operation in both direotions (up/ down) on the front windows, down only on the rear windows. • Anti-trap detention is on the front windows only (initialization required for one touoh oper¬ ation). • The oontrol of the rear windows is oarried out through a Relay Module (RM IV). • The switohes in the oenter oonsole oontrols all four windows and the rear window look out feature. Principle of Operation All window operation request signals are digital inputs to the GM. • Comfort Closing of the windows from the driver’s or passenger’s look oylinder when held in the looking position. • When the ignition key is in aooessory or “ON” press the switoh to open or olose the win¬ dows. Window operation is possible with the ignition switohed off until a front door is opened or 16 minutes (maximum) has elapsed. • Power proteotion against a jammed or seized motor is monitored by the hall sensors in the window motors. The GM will interrupt the power to a jammed motor. Rear windows utilize ourrent sensing for shut off. • The one-touoh funotion is aotivated by momentarily pressing the window switoh to the seoond detent. Window travel will oease when the full up or down position has been rea- ohed. One-touoh oan be oanoeled by pressing the window switoh a seoond time. Anti¬ trap is provided by the GM monitoring the door glass movement from the hall sensor. If the door glass enoounters resistanoe in the olosing direotion (>100Nm) the motor will stop and reverse direotion for 50 mm of travel. 20 Central Body Electronics ZKE IV Window Operation specific to the E36 Convertible: • Central Window Switch: Located in the center console, the switch will raise or lower all four windows at the same time. The window lowering has the one-touch feature. Convertible top operation: Prior to lowering the top, the top control module signals the CM to lower all four windows half way. - If the top switch is held after the top is fully lowered, the windows will close fully. - If the top switch is held after the top is fully closed the CM will close the windows. With the introduction of the fully automatic convertible top, the comfort close feature of the convertible was also added. Window Operation specific to the Coupe, Convertible and Z3 Coupe: The design of the E36 Coupe, Convertible and Z3 Coupe required changes in the window operation. • When opening the door, the door glass is automatically lowered by approximately 10mm. When the door latch opens (switch closes), the window will drop. It remains down until the door contact switch opens when the door is closed. The window will then raise back into the door seal. • When the door is closed, the glass is raised back into the seal. This allows the glass to drop out of the door seal when opening the door and provides a tighter seal when the door and glass are closed. • The window motor contains a Hall sensor for this feature that is monitored by the CM. 21 Central Body Electronics ZKE IV System Components Window Switches: The signals from the window switohes are monitored by the GM. The power window switohes have a seoond detent position for the purpose of signalling the one touoh feature. CLOSE OPEN Relay Module: The RM IV was added for rear window oper¬ ation in the 4 door and oonvertible models only. Similar to the front window relays in the GM, the Relay Module oontains the relays for the rear window motors on these vehi- oles. The RM IV is looated behind the glove box in the eleotrioal ear¬ ner next to the GM. System Components: Inputs - Processing - Outputs 22 Central Body Electronics ZKE IV Initialization of Window Circuits Initialization of the window oirouits is required for the one-touoh and anti-trap features to funotion. Closing the window and holding the switoh for an additional two seoonds will ini¬ tialize the system. However the window drive motor switohes off automatioally after the motor oeases rotation for approximately 0.3 seoonds. Sunroof Purpose of the System When the ignition key is in the aooessory or “on” position press the switoh to lift (1), olose the sun¬ roof (2) or open the sunroof (3). When lifting, the headliner retraots several inoh- es. The sunroof oan oontinue to operate after the ignition has been switohed off (up to 16 minutes) as long as one of the front doors has not been opened. E36 vehioles are equipped with the steel roof while the Z3 Coupe is equipped with the glass (moon) roof. Meohanioally, the sunroofs are sim¬ ilar in design. Principle of Operation The motor inoorporates a sunroof module (>96 MY) whioh reoeives inputs from the sunroof switoh (1) for operation. This sunroof system has the one touoh open funotion. The sunroof module is linked to the CM for two purposes: • The oomfort olosing feature when the key is held in the look position in one of the door look oylinders. • Unloader signal. This signal (30h) informs the sunroof motor module to stop running the sunroof motor when the CM reoeives a start signal (KL 50). 23 Central Body Electronics ZKE IV System Components: Inputs - Processing - Outputs Notes: 24 Central Body Electronics ZKE IV Interior Lighting Purpose of the System The GM controls the interior lighting automatioally with the status ohange of several monitored inputs. The lighting oan also be manually oontrolled using the interior light switoh (2). In addition to the various time oontrols, the interior lights are also subjeot to the 16 minute shut down of the GM (oon- sumer proteotion). Principle of Operation The interior light switoh is a rooker switoh that will aotivate the interior lights “On or Off” (left/right positions). When the light switoh is in the oenter position (automatio): • If the interior lights are switohed “ON” by the button with the ignition switohed ON, the interior lights will remain on until they are switohed off by the button. • If the interior lights are switohed “ON” when the ignition is switohed OFF, the lights will remain on for 16 minutes (oonsumer outout). • Looking the vehiole from the outside will immediately switoh off the interior lights. The ON/OFF oonditions for the interior lights in the automatio mode are as follows: ON Conditions • Door Open. • Switohing off ignition after exterior lights have been switohed off. • Grash Alarm/MRS input. 25 Central Body Electronics ZKE IV OFF Conditions • All doors olosed with ignition on. • All doors olosed with ignition off after 20 seoonds. • 20 seoonds after switohing off ignition with lights off. • 8 seoonds after switohing the ignition off. • 16 minutes with door(s) open. • When doors are looked. System Components: Inputs - Processing - Outputs 26 Central Body Electronics ZKE IV General Functions of ZKE IV Consumer Cut Off The Consumer Cut Off function interrupts battery voltage to circuits preventing inadvertent battery drain if one of the consumers were to remain activated. The CM will deactivate the interior lights after 16 minutes if one of the doors is left open. Convertibles also have the following lighting circuits controlled by this feature: • Glove Box Light • Trunk Light The circuit will switch back on when any monitored wake up trigger such as the door con¬ tacts or the lock/unlock signals become active. Overload Protection The Central Locking circuit of the GM is protected against overloads and short circuits by the electronic Overload Protection which is an integral part of the GM. • Power protection for the door locking circuit is provided by a “time monitored” activation of the door lock actuators by the GM. The door lock actuators are provided power for the duration of time needed to run the actuator to the desired position. The maximum on time for the actuators is 0.7 seconds. Review Questions 1. List the functions directly controlled by the GM IV, 2. How does the GM IV reoognize the key position from the drivers door?. 3. What is the “Gomfort Glosing” feature? 4. Desoribe the differenoes between “single” and “double” look regarding the look aotua- tors. _ 5. What oirouits are oontrolled by Gonsumer Gut Off? 6. What funotions will deaotivate the Interior Lighting? 7. Desoribe Blooking Proteotion: 8. What affeot does EWS have on the Gentral Looking System? 28 Central Body Electronics ZKE IV