1998 BMW 540i key

Table of Contents
SubjectPage
Central Body Electronics (ZKE III) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Objectives of the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Purpose of the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Power Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Windshield Wiping/Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Headlight Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Rear Window Wiper/Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Rain Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Central Locking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Trunklid/Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Remote (Keyless) Entry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Car Memory/Key Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Anti-Theft (DWA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Power Windows/Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Interior Lighting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Visual Entry Aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Seat/Mirror/Steering Column Memory. . . . . . . . . . . . . . . . . . . . . . . . . . 58
Seat Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Steering Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
General Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
Consumer Cut Off/Overload Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Sleep Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Review Questions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

2
Central Body Electronics ZKE III
Objectives of the Module
After completing this module, you will be able to:
• List the functions directly controlled by the GM III.
• Describe how the GM III recognizes the key position from the drivers door.
• Explain what “convenience” features are available from the FZV key.
• Describe how the Seat Module communicates a request for a stored memory position
with the mirror modules.
• List what circuits are controlled by Consumer Cut Off.
• Demonstrate how to Emergency disarm DWA.
• Describe the changes in the 2000 MY Key.
• Explain the electronic influence on power steering assist (Servotronic).
• Demonstrate how to open the sunroof (in the event of an electrical malfunction).
CENTRAL BODY ELECTRONICS (ZKE III)
Models: E38 - 740i(L) and 750iL
E39 - 525i, 528i, 530i, 540i and M5
E53 - X5 3.0i and X5 4.4i
Production Date: E38 1994 to Present
E39 1997 to Present
E53 1999 to Present
Manufacturer: Hella
Pin Connectors: White - 26 pin, Black 26 pin, Black 20 pin (large)

3
Central Body Electronics ZKE III
Central Body Electronics (ZKE III)
Purpose of the System
The Central Body Electronics (ZKE III) system manages the following functions:
GM III
• Windshield Wiping/Washing
• Windsheild Rain Sensor (AIC)
• Headlight Washing
• Tailgate Wiping/Washing
• Interior Lighting
• Central Locking
• Keyless Entry
• Key Memory
• Power Trunk Release
• Electric Opening of Tailgate
• DWA Alarm System
• Servotronics
• Consumer Cut-off/sleep mode
• DiagnosisDriver’s Door Switch Block/
Module
• Power Windows
• Mirror Adjustment/Memory/
HeatingPassenger’s Door Module
• Mirror Adjustment/Memory/
Heating
• Power Windows
Sunroof Module
• Power SunroofSeat/Mirror/ Steering Column
Memory Module
• Seat Adjustment/Memory
• SteeringColumn Adjustment/
Memory
The ZKE III system was introduced on the E38 and is used in the E39 and E53. Most of the
functions operate the same on these vehicles with minor changes and added features to
the system.
ZKE III represents the combination of Body Electronics functions into one central control
module, the General Module (GM).

6
Central Body Electronics ZKE III
The following is an overview of new or changed features found on the E53 ZKE III variant:
• Passenger’s door module is incorporated into the passenger’s door switchblock.
• Sunroof module (SHD) is located on the P -Bus.
• The Central Locking system uses a door lock actuators with hall effect sensors.
• The GM III is responsible for the Key Memory feature.
The E53 ZKE III system continues to be a modular system consisting of the following:
•General Module III = Main controller for ZKE functions
•PM - SB/FT = Driver’s door switch block and door module
•PM - SB/BT =Passenger’s door module/Window switch
•PM - SHD =Sunroof module
•PM - SM =Seat/Mirror/ Steering Column memory module
•AIC = Rain Sensor (if equipped)
All of these modules communicate over the “K-Bus and P-Bus” for signaling purposes and
diagnosis.

10
Central Body Electronics ZKE III
Blocking Protection = Return
Contact Signal must be
present every 16 seconds
or motor will be deactivated >98 MY
1.49v-3.5v
Headlight Washing (if equipped):When the headlights are on, the headlight washer
pump is activated with the first activation of the windshield washer pump. It is only activat-
ed again after five succesive windshield washer cycles during the same ignition key on cycle
(rest function). The GM recognises headlights on via K-Bus signalling. The GM provides a
ground on the headlight washer relay control circuit providing pump operation. The head-
light washer pump is located on the side of the washer fluid reservoir.
System Components: Inputs - Processing - Outputs
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E53 Shown

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 or the
remote (key-less) entry, a lock/unlock request will
lock/unlock all exterior doors, luggage compart-
ment and the fuel filler flap.
From inside, the vehicle can be locked/ unlocked using a cen-
tral locking button located in the center console. Individual
doors can be unlocked manually by pulling twice on the inte-
rior door handle.
From 2000 MY
- if the vehicle has been double locked, press
the central locking button and pull the interior door handle
twice (alarm will sound when the door opens).
Locking the vehicle from the central switch will “single lock” all
doors, luggage compartment and not lock the fuel filler flap.
The Central Locking System utilizes the GM III and Door Modules to carry out all of the lock-
ing/unlocking features:
• Remote (key-less) entry is standard.
• When locked from the outside, the vehicle will double lock and arm the DWA System. The
ignition must be switched off and the driver’s door must be opened and closed.
• Selective unlocking from the outside of the vehicle. Unlocking from the driver’s door or
remote transmitter will only unlock the driver’s door and disarm the DWA System. A sec-
ond request will unlock the remaining doors and luggage compartment. This feature can
be modified for individual users in Key Memory to open all doors from a single request.
• A single central locking button is installed in the center console that will operate when all
of the doors are closed. Locking the vehicle from the central switch will “single lock” all
doors, luggage compartment and not lock the fuel filler flap. When unlocking, a single
request will unlock the driver’s door only. This feature can be modified for individual users
in Key Memory to open all doors and luggage compartment from a single request.
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Central Body Electronics ZKE III
12510117.jpg
12510118.eps

• A remote luggage compartment button is installed in the left kick panel (center console
in the E53) to open the luggage compartment from inside the vehicle.
• The EWS is interfaced for double lock monitoring and unlock function. With the presence
of an accepted EWS key in the ignition, the vehicle will be unlocked and disarm DWA.
• The automatic locking feature (> 99 MY) activates the door locks when a road speed
signal of 5 MPH and engine RPM is detected via the K-Bus. The factory default setting
of this feature is off (can be encoded on for individual users with Key Memory function).
• In the event of an accident (ignition on), the GM will be signalled to unlock all doors.
Hardware Features:
• The external lock cylinders are located in the
driver’s door and luggage compartment lid
(E53/E39 Sport Wagon does not have a tail-
gate lock cylinder).
• The driver’s door and luggage compartment
incorporates an overrunning lock cylinder. The
lock cylinder will free wheel or spin If any key
other than the vehicle key or tool, such as a
screw driver, is inserted into the cylinder. The
lock cylinders can be manually locked/un-
locked by turning the key “past” lock/unlock.
• The door lock buttons are mechanically uncoupled from the
lock actuators when locked.
The door lock buttons “mechanically” lock the individual
doors. This provides manual locking in the event of a central
locking malfunction.
• Child safety locks (located in
the rear doors) are actuated
by inserting a key in the slot on
the door latch or by sliding a
lever (dependent on model).
The door can now only be
opened from outside.
18
Central Body Electronics ZKE III
Door
Button
Lock
12520117.eps
12520119.eps
12510121.eps
12520120.eps

• 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 luggage compartment release button in-
side the vehicle will also be ignored by the GM.
Prior to 2000 MY the vehicle could be locked/
unlocked using the luggage compartment lock
cylinder.
• The glove box has a lock cylinder to secure the
contents by manual locking with a “Master
Key” and leaving the lock cylinder in the hori-
zontal position which prevents opening by any
other method (secured for valet).
• The E38 has a lever behind the glove box han
dle which permits locking the glove box with-
out a key. Opening still requires a key.
The valet key is not mechanically capable of
entering either of these lock cylinders.
• The Fuel Filler Flap mechanical release is found
in the right side of the luggage compartment.
The “pull tether” is behind the button as shown
on the right.
Note: Continuous operation of locking/unlocking will cause a timed arrest of the
locking system. When activated, the timed arrest lasts for 2 minutes (or recycle
the ignition KL15). The “crash” signal will override the timed arrest and unlock the
vehicle.
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Central Body Electronics ZKE III
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12520121.jpg
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