
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).  

5
Central Body Electronics ZKE III
The ZKE III system offers an overall reduction in vehicle wiring particularly in the areas sub-
ject to wear from movement such as doors, seats and the steering column. To accomplish
this, the “P- Bus” is used to interface (signaling) with peripheral modules over a single wire.
The ZKE III modular system consisting of the following components:
• General Module III  = Main controller for ZKE functions
• PM - SB/FT            = Driver’s door switch block and door module
• PM - BT                  = Passenger’s door module
• PM - SHD               =Sunroof module
•PM - SM                 =Seat/Mirror/Steering Column memory module
• AIC                         = Rain Sensor (if equipped)
All modules communicate through the P-Bus and GM III onto the K-Bus for diagnosis. 
PM-FT/SB
PM-SMPM-BT
PM-SHD
P-BUS
K-BUS
Driver's Door
Switchblock/
ModuleDriver's Door
Switchblock/
Module
Seat Memory
ModuleSeat Memory
Module
Passenger's
Door ModulePassenger's
Door Module
Sunroof
ModuleSunroof
Module
GM IIIFBZVFBZVDWADWA
FBZV
RECEIVER
MODULE
GM III MODULE
LOCATED IN CARRIER
FORWARD OF GLOVE BOX
Separate
Switch and
Module < 96
E38 on K-Bus
>99 MY
12520102.eps 

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. 

System Components 
- with the Principle of Operation
Driver’s  Door  Lock: The  lock/unlock  signals
from  the  driver’s  door  lock  cylinder  are  input  to
the  driver’s  door  module  from  the  two  micro
switches  on  the  lock  cylinder.  The  driver’s  door
switchblock module carries out the locking func-
tion of the driver’s door.  
The  windows  and  sunroof  can  be  closed  or
opened  by  holding  the  key  in  the  lock/unlock
position (convenience closing/opening feature). 
The  signal  to  lock  the  remaining  doors  and  fuel  filler  flap  is  passed  over  the  P-Bus  to  the
GM III and passenger’s door module. The locking of the passenger’s door is carried out by
the  passengers  door  module.  The  rear  doors,  luggage  comparment  and  fuel  flap  locking
are carried out directly by the GM III. All four doors will be pulled into the double lock posi-
tion when locking from the driver’s door.
The control of the actuators in the front doors is through final stages in the door modules.
The rear doors, trunk and fuel filler flap actuators are controlled by internal relays in the GM
III. When locked, the GM III will not carry out any opening commands from the central lock-
ing button or luggage comparment interior release button.
Luggage  Compartment  Lock  Cylinder  (except  E53/E39  Sport  Wagon): The  vehicle
can be locked/ unlocked (prior to 2000 MY) from the luggage compartment lock cylinder.
The lock/unlock micro switch inputs are processed in the GM III and the locking commands
are carried out. 
The signal is passed over the P-Bus to the
door  modules  to  lock/unlock  the  front
doors  and  the  GM  III  locks  the  rear  doors
and fuel filler flap. 
All door actuators are placed in the double
lock position. Removing the key in the hor-
izontal position will activate the valet mode
and prevent the valet key from opening the
luggage comparment.
20
Central Body Electronics ZKE III
12520123.eps
12520124.eps 

Remote (Keyless) Entry FZV
Purpose of the System
The Remote Entry System offers the following:
• Locking/unlocking of doors, luggage compartment (tailgate), fuel filler lid.
• Selective unlocking of driver’s door (same as with key in the lock cylinder).
• Arming/disarming of DWA alarm system.
• Remote unlocking of the trunk (tailgate) only.
• Comfort opening of windows and sunroof.
• Interior lighting activation (search mode).
• Panic mode alarm activation.
• Changing code signals - coded signals from transmitter change with every operation.
• Automatic correction for up to 1000 erroneous activation signals.
• Transmitter initialization procedure - including up to four key operation and Key Memory.
• Replacement batteries.
• Low transmitter battery in vehicles equipped with Check Control. 
26
Central Body Electronics ZKE III
615200098.eps 

Power Windows/Sunroof
Purpose of the System
The features of the power windows and sunroof system include:
• One-touch operation in both directions (up/  
down) on all four windows.
• The  cable  design  window  regulator  is  used
for all windows.
• Anti-trap detection is through the use of the
pressure sensitive finger guard. 
• The  control  of  the  front  window  motors  is
carried out in the respective door modules.
• The  control  of  the  rear  windows  is  carried
out in the GM III.
• The  switch  block/module  on  the  driver’s
door panel controls all four windows and the
rear window lock out feature.
System Components
- with the Principle of Operation
The signals from the switch block pass through
the  driver’s  door  via  the  P-Bus  and  on  to  the
GM III and passengers door module. 
Each window switch has four positions.
Two for the standard mode of operation:
• Push to first detent and hold to raise/lower  
the window (1). 
Two for the one-touch mode:
• Push to second detent and quickly release  
(quick strike) to automatically raise/lower  
the window (2). 
42
Central Body Electronics ZKE III
1
2
Rear Windows
Lock Out
Switch