
4
Central Body Electronics ZKE III
System Components
General  Module  (GM): The  GM  is  reponsible
for  the  operation  and  central  coordination  of
body  electronics.  The  GM  is  a  micro-computer
that  is  the  central  component  (heart)  of  the
Central Body  Electronics. The GM is located be-
hind the glove box. 
The main objectives for using the GM are:  
The  GM  requires inputcommands  to  perform
Central  Body  Electronics  functions.  The  inputs
are  supplied  by  digital  switched  signals  such
as:
• Trunk Lock Microswitch - supplies voltage (KL  
30) to the GM when switched. A path to gro-  
und is provided by the GM (internally). The 
GM monitors the switched input voltage. 
• Central Lock Button - supplies a ground cir-   
cuit to the GM when switched. The GM sup- 
plies and monitors a reference voltage (5v)     
that is “pulled” low when the switched gro-
und path is provided.  
The  GM processesthe  input  information  and
contains “coded” instructions that allow a spe-
cific output control of functions.
The  GM  will  produce outputfunctions  using
internal  transistors  to  switch  current  flow  (pro-
viding  voltage  or  ground)  through  circuits  and
actuators.  Actuators  are  the  final  controlling
devices  used  by  the  GM  to  operate  or  control
various  output  functions  such  as  relays  and
motors.
• Increase Overall Reliability 
• Centralize Electronic Systems
• Decrease Assembly and Service Repairs 
• Centralized Diagnosis of all ZKE Components 
• Individualization of Features (Coding) 
CENTRAL LOCK BUTTONCENTRAL LOCK BUTTON
TRUNK LOCK BUTTONTRUNK LOCK BUTTON
KL 30KL 30
TRUNK LOCK MICROSWITCHTRUNK LOCK MICROSWITCHSignal Monitor
5v
Supply/
Monitor
GM
FUEL 
FILLER
FLAP 
RELAY
Transistors
GM
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Central Body Electronics ZKE III
Power Distribution
The power distribution box for the
E38  is  incorporated  in  the  Electr-
onics  box  in  the  engine  compart-
ment. 
The power distribution box for the
E39 and E53 is inside the vehicle. 
The  main  fuse  box  is  located
inside  the  glove  box  above  a
hinged panel. 
A  “pull  out”  fuse  designation  card
is also located in the fusebox. This
notes:
• Fuse value in amps
• Location
• Circuit listing by fuse
The placement of the power distribution box is
close  to  the  main  electronics  carrier behind
the  glove  box.  The  modules/relays  located  in
the electronics carrier include (examples):
• General Module III (GM III)
• Drive away protection (EWS II)
• Anti-lock Brake (ABS/ASC+T)
• Light Check Module (LCM) - behind right kick
panel
• Overload protection relay module
An  auxiliary  fuse  block  is  located in  the  trunk
above  the  battery.  In  addition  to  fuses,  the
auxiliary fuse block also contains relays (exam-
ples):
• Fuel filler flap lock motor relay
• Fuel pump relay (some vehicles)
• Rear defroster relay
• Unloader relay 
FUSE
DESIGNATION
CARDFUSE BOX DROPS
DOWN AFTER TURNING
TWO THUMB SCREWS
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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
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• 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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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.
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Central Body Electronics ZKE III
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• Key  in  the  neutral  position,  both  sensors  are
simultaneously  influenced  by  the  magnet  -
0/0.
• Key  turned  to  the  unlock  position  from  neu-
tral,  hall  sensor  #1  magnet  segment  moves
away from hall sensor - 1/0.
• Key  turned  to  lock  position  from  neutral,  hall
sensor  #2  magnet  segment  moves  away
form hall sensor - 0/1.
There  are  two  motors  incorporated  in  each  actuator
that provide two separate functions:
Single  lock/unlock  function:  Also  known  as  central
lock,  this  motor  controls  the  mechanical  lock  mecha-
nism when the central lock button is pressed to single
lock the vehicle. 
The lock mechanism is fully locked at this point but can
still be opened from the interior by pulling the appropr-
iate interior door handle twice or by pressing the cen-
tral lock button again. When single lock function is acti-
vated, the fuel filler flap actuator is not locked.
Double lock/unlock function: Also known as central
arrest,  this  motor  is  activated  only  when  the  vehicle  is
locked from the exterior at the driver’s door lock with a
key  or  when  the  GM  receives  a  lock  request  from  the
Key-less  entry  system.  In  this  case  the  double  lock
motor  is  activated  simultaneously  with  the  single  lock
motor. 
The  function  of  the  double  lock  motor  is  to  mechani-
cally offset an internal rod disabling it from unlocking 
the vehicle from the interior. This prevents the doors  
from being unlocked by any means except from an  
unlock request at the driver’s door or via the Key-less  
entry.
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Central Body Electronics ZKE III
HALL SENSOR 1
HALL SENSOR 2
PLASTIC CYLINDER
WITH ASYMMETRICAL MAGNET
(Shown in the Lock Position)
SINGLE
LOCK
MOTOR
DOUBLE
LOCK
MOTOR
ACTUATOR IN UNLOCKED POSITION
ACTUATOR IN LOCKED POSITION
WHEN IN DOUBLE LOCK AN
INTERIOR ACTUATED UNLOCK
ROD IS OFFSET PREVENTING
THE LOCK MECHANISM FROM
BEING MECHANICALLY
UNLOCKED 

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. 
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Central Body Electronics ZKE III
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