1999 BMW 540i Electrical System

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Central Locking and ~nti-~heel
Door latch, removing and installing
- Close window on subject door and open all other windows.
- Disconnect battery negative (-) cable
CAUTION-
Prior to disconnecting the batterl: read the battery discon-
nection cautions given in
001 General Warnings and Cau-
tions.
- Remove door trim panel. See 411 Doors.
- Remove air bag. See 721 Airbag System (SRS).
- Remove outer door handle. See Door handle (outer), re-
moving and installing.
< Working inside door cavity, release loclting tabs (arrows)
and open protective cover.
Pull down on electrical harness connector (arrow) to re-
lease.
< Working inside door cavity, next to outside door sltin:
Disconnect door lock cylinder Bowden cable from latch as-
sembly arm
(A) and support (B).
Disconnect microswitch connector (arrow).

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51 5-21
Central Locking and Anti-Theft
Trunk lid gap
measurements 4 When installing, or adjusting trunk lid alignment, adjust posi-
tion of trunk
loclc striker with mounting bolts finger tight.
* Check trunk lid loclc operation with lid open.
Adjust trunk lid alignment. See
412 Trunk Lid, Tailgate for
lid adjustment specifications.
NOTE-
Do not lubricate lock or lock striker with grease.
Tailgate lock, emergency release
4 In case of electrical failure, there is an emergency tailgate
loclk release. The release is located in the tailgate behind the
tool door.
- With tool door open, remove access cover and pull to the
right to release tailgate.
ELECTRONIC ~MMOBILIZATION (EWS)
E39 cars are equipped with a passive theft-prevention sys-
tem. The Electronic Immobilization System (EWS) makes it
impossible to
startthe engine using any means other than the
special lkeys furnished with the vehicle.
NOTE-
Replacement EWS control modules or DME control modules
must be electronically aligned to each before the vehicle will
start. This requires the use of the BMW Service Tester
(DIS-
plus, GT1, or MoDiC). Without alignment, the engine will not
crank (for example: swapping a
known good DME control
module into another vehicle for test purposes will result in a
no crank situation).
In the EWS system, the ignition key is embedded with
acom-
puter chip (EEPROM) and coded. The key communicates
with the vehicle using a transponder in the lkey and a ring an-
tenna surrounding the steering lock cylinder. Up to
6 replace-
ment keys are permissible. Only an authorized
BMW dealer
can provide replacement keys.

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Central Locking and Anii-Theft
- If the starter engages, the following EWS inputs are function-
ing normally:
Ignition key
Code function
Transmission range switch or clutch position switch
Engine speed sensor
NO JE -
If a vehicle key is lost or stolen, the electronic authorization
for that key
can be cancelled using the BMW scan and di-
agnostic tools
DISplus, GTl or MoDiC.
Force applied to a ley can damage the electronic circuitry
in the key A damaged ley will not start the engine. In that
case, a new key should be purchased and initialized
by an
authorized BMW dealer.
EWS variations
EWS variations used in E39 cars are shown in E39 EWS ap-
plications
table below.
E39
EWS applications
I I Ifling antenna (surrounds ignition switch) I
System
designation
EWS
II
I I l~ransmitter I receiver module located in right side steering column cover I
E39 production
dates
SOP
- 311 997
I I IEWS 111 (3.2) control module incorporates transmitter1 receiver moduie functions /
Main components, changes, improvements
Key with EEPROM transponder
Control moduie located behind glove compartment, in electrical component panel
Control module located to left of steering column, under dashboard
K-Bus input
Transmitter
I receiver module eliminated
EWS 111 (3.2)
Transmission range selection input from automatic transmission control module
3
11997 - 911997
- EWS ill (3.3) Clutch
Hall-effect switch (replaces transmission range switch input)
911997 - 2002 EWS 111 (3.3) control
module with iSN code burned in (cannot be overwritten during
alignment)
Control module located to left of steering column, under dashboard

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l Seats
Seat repair and component replacement is possible once the
seat has been removed from the vehicle.
Before servicing front seats read safety regulations on han-
dling
airbag modules and pyrotechnic seatbelt tensioners.
See
720 Seat belts and 721 Airbag system (SRS).
WARNING-
. The front seats are equipped with pyrotechnic seat belt
tensioners. These tensioners are powerful devices and
should be handled with exfreme care. Incorrect handling
can trigger off the tensioner and cause injury.
BMW recommends that all repair or replacement
worlc
on pyrotechnic devices must be carried out by a quali-
fied
BMW technician.
Be sure to disconnect the battery and wait
5 seconds
before attempting to work on pyrotechnic devices.
During body straightening and welding with an electric
arc welder, always disconnect the battery and the con-
nection to the pyrotechnic gas generators.
Seat switch and memory module, removing
and installing
- Remove front seat. See Front seats, removing and install-
ing.
- Carefully pull seat adjusting ltnobs straight out to remove.
Remove screw fastener
(A) and trim clips (B), turn side panel
downward to remove.
Disconnect electrical harness connector
(arrow).

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Airbag System (SRS)~
MRS control module, replacing
- Disconnect negative (-) cable from battery and cover nega-
tive terminal with insulating material.
CAUTIOI\C
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven in001 General Warnings and
Cau-
tions.
- Remove center console between front seats. See 513 lnteri-
or Trim.
Remove module mounting nuts (arrows) and lift up control
module. Disconnect electrical harness connector.
Installation is reverse of removal.
Be sure that MRS control module ground cable is attached
to the module mounting stud.
Side-impact crash sensor, removing and
installing
- Make sure ignition key is OFF.
- Remove front seat. See 520 Seats.
Remove plastic door sill trim by lifting to release clips at one
end, then sliding off. Fold up carpet towards rear seat floor. If
necessary, remove floor level heater duct.

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721 -8
(Airbag System (SRS)
4 Remove electrical harness connector from crash sensor (A).
Remove sensor retaining screws (6) and remove sensor.
Note direction of sensor before removing.
- Installation is reverse of removal,
NOTE -
Arrow on sensor must point to door sill.
Driver airbag, removing and installing
- Disconnect negative (-) cable from battery and cover nega-
tive terminal with insulating material.
WARNING-
After disconnecting the batter)! wait 5 seconds before begin-
ning work on
airbag components.
CAUTION-
Prior to disconnecting the batter)! read the battery discon-
nection cautionsgiven
in001 General Warnings and Cau-
tions.
4 Multifunction (MFL) steering wheel:
. Working behind steering wheel, completely loosen Torx
screws
(T30) while holding airbag in place.
Support
airbag unit to prevent it from falling out.

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721 -9
Airbaq System ~SRS)~
4 Sport steering wheel:
Insert screwdriver through opening in rear of steering
wheel and push against spring tension to release
airbag
unit lock.
Repeat procedure on other side of steering wheel.
Lift off
airbag unit and detach electrical harness connec-
tors.
WARNING-
Store the removedairbag unit with the horn pad facing up.
If stored facing down, accidental deployment could propel
it violently into the air, causing injury.
Once an
airbag is removed, the car must not be driven.
Do not connect the battery with the
airbag disconnect-
ed. A fault code will be stored, setting off the
airbag in-
dicator light Special tools are needed to reset the fault
memory
Once the
airbag unit is installed and all other service
procedures have been completed, start the engine and
check that the
airbag indicator light goes out. If the in-
dicator light stays on, the
airbag system will not func-
tion as designed. Have the system diagnosed and
repaired by an authorized
BMW dealer.
- Installation is reverse of removal.
MFL steering wheel: Torque airbag using specification list-
ed below.
- Sport steering wheel: Press airbag unit mounting pins into
spring
loclts in steering wheel until they snap in firmly.
CAUTION--
Do notpinch airbag harness in center of steering wheel when
installino
airbaa.
Tightening torque
Airbao to steerino wheel IMFL) 8 Nm (71 in-lb)
Passenger airbag, removing and installing
- Disconnect negative (-) cable from battery and cover nega-
tive terminal with insulating material.
--
WARNING -
After disconnecting the batteg wait 5 seconds before begin-
nina work on airbaa components.
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven in001 General Warnings and
Cau-

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721 -1 0
/Airbag System (SRS)
4 Pry up cover from top of passenger side airbag on dash-
board.
4 Remove airbag mounting bolts (arrows)
- Lift airbag and disconnect electrical harness connector. Re-
move
airbag.
WARNING-
Store the removed airbag unit with the soft pad facing up. If
stored facing down, accidental deployment could propel it vi-
olentlv into the
ail: causino inium
- Installation is reverse of removal. Make sure wiring harness
is not pinched when installing
airbag unit in dashboard.
Tightening torques
-
Passenger alr bag to 10 NM (88 in-lb)
dashboard (Me)
Door mounted side-impact airbag,
removing and installing
- Disconnect negatlve (-) cable from battery and cover nega-
tive terminal with insulating material.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions given
in 001 General Warnings and Cau-
tions.
- Remove inside door panel as described in 41 1 Doors