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400-8
Body-General
Airbags
Front airbags, s~de a~rbags, pyrotechnic seat belt tensioners
and the Battery Safety Terminal (BST) are integrated into the
Supplemental Restraint System (SRS) and its variants.
NOTE-
The BMW SRS system is called Multiple Restra~nt System
(MRS). Over the years,
E39 cars were equipped with MRS,
MRS
11, MRS 111. Each version offers varied features and im-
provements over the previous system.
< As many as 8 airbags may be installed in E39 cars, depend-
ing on model and MRS version.
The front
airbags operate without sodium azide propellant,
widely considered an irritant when an
airbag is deployed.
Starting with
1999 models. "smart"front passenger and driver
airbags were installed. These are of the dual-threshold, dual
stage design, including a
sensorto help prevent the unneces-
sary deployment of the passenger side
airbag if the seat is un-
occupied.
MRS control Depend~ng on options chosen, one airbag may be installed in module each door of the sedan and Sport Wagon models, protecting
passengers against
s~de impacts.
Head Protection System (ITS)
airbags strelch diagonally
across the tops of the front doors.
Airbag deployment automatically triggers fuel shutoff, turns
on the hazard and interior lights, and unlocks the doors.
- -
WARNING -
Airbags are inflated by an explosive device. Handled im-
properly or without adequate safeguards,
airbag units can
be very dangerous. Special precautions must be observed
prior to any worlc at or near any of the airbags. See
721 Air-
bag System (SRS).
Always disconnect the battery and cover the negative
(-) battery terminal with an insulator before starting di-
agnostic, troubleshooting or service work on cars fitted
with SRS, and before doing any welding on the
car.
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51 5-2
/Central Locking and Anti-Theft
This section covers repair information for door, trunk and car-
go compartment locks, central locking, electronic
immob~liza-
tion (EWS) and anti-theft alarm (DWA).
€39 cars are equipped with sophisticated self-diagnostic elec-
trical systems. When experiencing malfunctions relating to
central locking. EWS or anti-theft systems, start the diagnosis
process using the
BMW service tester DIS, GT 1, MoDiC or
equivalent scan tool. An advanced diagnostic scan tool can
usually pinpoint electrical faults quickly and safely.
Additional electrical information can be found in:
610 Electrical Component Locations
ELE Electrical Wiring Diagrams
Central locking in E39 vehicles controls the door
locks, trunk
or tailgate lock and fuel filler flap lock. The control module for
the Central Body Electronics system (ZKE
Ill), lknown as the
General Module (GM
Ill), controls central locking.
ZKE
Ill manages the following central locking related func-
tions:
Central locking
* Keyless entry
Key memory
Power trunk release
Electric opening of tailgate
DWA alarm system
Diagnosis
General Module
4 The General Module (GM) (arrow) is responsible for the op-
eration of central body electronics. The GM is located behind
the glove compartment.
Based on input information, the GM uses internal transistors
to switch current flow (providing voltage or ground) through
circuits and actuators. Actuators are the final controlling de-
vices used by GM to operate or control various output func-
tions such as relays and motors.
The accompanying schematic, Central locking inputs and
outputs, illustrates the GM central locking system.
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51 5-4
I Central Locking and Anti-Theft
Driver's door lock
The
lock/unlock signals are sent as input to the door module
from two microswitches on the lockcylinder. The driver's door
module carries out the locking
/ unlocking functions of the
driver's door through its final stage control.
The signal to lock the remaining doors, trunk or tailgate and
fuel flap is sent over the P-Bus to the GM and the passenger
door module. Activation of the passengers door
loclt is carried
out by the passenger door module. The rear doors, trunlt or
tailgate and fuel flap are
locked by the f~nal stage in the GM.
When
locked from the outside, all doors are set to the double
lock position and the GM will not carry out any unlock com-
mands from the central
loclc button or remote trunk release
button.
Selective unlocking
When unlocking with the key or the remote transmitter, the
first unloclcrequestwill only unlock the driver'sdoor. A second
unlock request will unlock the remaining doors, trunk or tail-
gate and fuel flap.
Trunk locking
I
The vehicle can be locked/unlocked from the trunlc loclc cylin-
der. The GM locks the trunk or tailgate, rear doors and fuel fill-
er. The locking command is passed over the P-Bus to the
respective door modules to lock the driver's and passengers
doors.
Locking the trunk and removing the key in the
hor~zontal posi-
tion will set the valet lock and prevent opening of the trunlt
with the central locking system.
Central locking switch
-
< The central locking master control switch (arrow) is located
in the center console behind the shifter.
The central locking button will only single
loclt the doors
and trunk. The filler flap remains unloclted for refueling pur-
poses.
If a door is opened from inside while centrally locked, the
remaining doors remain locked.
The open door can be relocked, when closed, by manually
locking or pressing the central locking button twice. This
synchronizes the door
locks.
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51 5-6
(Central Locking and Anti-Theft
Each rear door is equipped with the child lock-out lever, pre-
venting the door from being opened from the inside regard-
less of loclc button position.
Starting with models produced afler
911997, the General
Module and electronic immobilizer (EWS) interface via the
K-
Bus to monitor double lock status and to initiate double loclc
override. This feature allows the doors to be opened from the
inside if a key accepted by EWS is switched on in the ignition.
See Single lock and double lock function.
The door loclc buttons are mechanically uncoupled from the
actuators when locked. The remote keyless entry system
(FZV) is standard equipment. This allows for elimination of
the passengers side door
loclt cylinder.
Another function of the locking system is the
sofl close trunk
(SCA) system, where applicable.
Single lock and double lock function
(2000 and later models)
On models produced after
911999, each door lock actuator in-
corporates two motors:
Single lock motor controls the mechanical loclc mechanism
when the central lock switch is pressed to single loclc the
vehicle. The loclc mechanism is fully locked at this point but
can stil. be openeo from
the interor by pulng the appropri-
are interior door nandle lwce or by pressing rhe central
lock switch again. When single
lock'function is activated,
the fuel filler flap actuator is not locked.
Double lock motor, also known as central arrest, is activat-
ed only when the vehicle is locked from the outside at the
driver's door lock with a key or when the GM receives a
lock request from the remote entry (FZV) system. In this
case the double lock motor is activated simultaneously
with the single lock motor. The function of the double loclc
motor is to mechanically offset an internal rod in the loclc
actuator, disabling it from unlocking the vehicle from the in-
terior. This prevents the doors from being unloclted by any
means except from an unlock request at the driver's door
or via the FZV remote key.
Lock cylinder safety
4 The driver's door loclc and the trunk loclc incorporate an over-
running loclc cylinder similar to the ignition lock. If any key
other than the vehicle key, or a tool such as a screwdriver or
dent-puller, is inserted into the cylinder, it will cause the cyl-
inder to freewheel or spin.
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Central Locking and Anti-Theft
Trunk lock
6 Tr~nk ftey pos~rions for eecir'cal mama, locking and
-nlock~ng are:
1. Manual unock .. - - - ........ - ..- .- ................. s.=.=-- 2. Unlock. DWA oisarmed, conven:ence open
(nold
un1:l aclivaledj
3. Ne~tral posit'on
1. -ocn. DWA armeo, Convenience closng
(hold ~nti activated)
5. Valet .oc,t position
. -- .............-... .- . - -.....
Key memory
< The remote trunk button (arrow) is located in the lefl lticlc
panel.
- The trunk can be opened from this remote release when the
doors are locked from the central locking button. The
trunk
remote button is disabled when the trunkis loclted in the valet
position or when a speed signal of
4 mph is present at the
GM.
Remote entry (FZV)
< The €39 remote (keyless) entry system (FZV) uses a tiny ra-
dio transmitter in the vehicle key to
lock and unlock the doors
and the trunk by remote control. There are a number of other
features incorporated in FZV:
Locltinglunloclting of fuel filler lid
Selective unlocking of driver's door (as with key in lock)
Armingldisarming of DWA alarm system
Remote unlocking of
trunk lid or tailgate
Comfort opening of windows and sunroof
* Interior lighting activation
Panic mode alarm activation
* Models to 1999: Key incorporates LED. LED informs oper-
ator that an FZV signal is being transmitted. LED is also
useful indicator of key initialization status and lkey self-test.
Keys delivered with four different colored labels. This is
helpful to differentiate FZV keys during initialization,
pre.
venting possibility of misassigning key ID which would
change coded Key Memory functions.
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721 -2
l~irba~ System (SRS)
This repair group covers airbag components and replace-
ment.
Airbag system repairand fault diagnosis is not covered.
Diagnostics, component testing, and
airbag system repair
should be carried out by trained BMW service technicians.
Individual
airbag system components can only be tested elec-
tronically when installed in the car. BMW service testers
DIS
or MoDiC or equivalent must be used for diagnostic work.
WARNING-
Special test equipment is required to retrieve airbag fault
codes, diagnose system faults, and
reseffturn off the air-
bag indicator light. The indicator light will remain on until
any problem has been corrected and the fault memory has
been cleared.
Airbags are part of the BMW Multiple Restraint System
(MRS). Three versions of MRS are available in E39 models.
Multiple Restraint Systems
MRS and MRS II include the following restraint components:
311 996-811 997
911
997-311 999
311 999-2002
Driver and passenger front
airbags (MRSIMRS II)
MRS
MRS
II
MRS Ill
Passenger front two-stage airbag (cars manufactured
from
911998).
The seat occupancy sensor (SBE) is used for detection of
a passenger in the right front seat. MRS uses the SBE in-
put to determine seat belt tensioner
and/or front airbag de-
ployment thresholds.
Side impact
airbag for driver and front passenger
(MRSIMRS II)
Leftlright side impact crash sensors (MRSIMRS 11)
Side impact airbag for rear passenger (MRS II) (optional)
Head Protection System (HPS) for driver and front passen-
ger (MRS
II)
Battery Safety Terminal - BST (MRS II)
Hall Sensor seat belt switches (MRS II)
Front pyrotechnic seat belt tensioners
Fuel pump cut off message
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OED-2
On-Board Diagnostics
Specialized OED II scan tool equipment is needed to access
the fault memory and
OED I1 data.
The extra hardware needed to operate the OED
I1 system
consists mainly of the following:
* Additional oxygen sensors downstream of the catalytic
converters.
Fuel tank pressure sensor and device to pressurize
fuel
storage system.
Several engine and performance monitoring devices
Standardized 16-pin
OED II connector under the
dashboard.
Upgraded components for the federally required reliability
mandate.
Malfunction indicator light (MIL)
OED II software illuminates the malfunction indicator light
(MIL) when emission levels exceed 1.5 times Federal
standards.
4 For E34 cars covered by this manual, three different MIL
symbols were used, depending on year and model.
MIL illuminates under the following conditions:
Engine management system fault detected for
two
consecutive OED iI drive cycles. See Drive cycle in this
repair group.
- Catalyst damaging fault detected.
Component malfunction causes emissions to exceed 1.5
times OED
II standards.
Manufacturer-defined specifications exceeded. Implausible input signal.
Misfire
faults.
Leak in evaporative system,
Oxygen sensors observe no purge
flow from purge valve 1
evaporative system.
ECM fails to enter closed-loop operation within specified
time.
ECM or automatic transmission control
module (TCM) in
"limp home" mode.
ignition key ON before cranking (bulb
check function).
OED
II fault memory (including the MIL) can only be reset
using a special scan tool. Removing the connector from the
ECM or disconnecting the battery does not erase the fault
memory.
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- -
On-Board Diagnostics
Professional diagnostic scan tools available atthe time of this
printing include the BMW factory tools
(DISplus, GTI,
MoDiC) and a small number of aftermarket BMW-specific
tools. See
020 Maintenance.
In addition to the professional line of scan tools, inexpensive
generic OBD
II scan tool software programs and handheld
units are readily available. Though limited, they are
nonetheless powerful diagnostic tools. These tools read live
data streams and freeze frame data as well as a host of other
valuable diagnostic data.
Diagnostic monitors
Diagnostic monitors run tests and checks on specific
emission control systems, components, and functions.
A complete drive cycle is requiredforthe tests to bevalid. See
Drive cycle in this repair group. The diagnostic monitor
signals the
ECM of the loss or impairment of the signal or
component and determines if a signal or sensor is faulty
based on
3 conditions:
* Signal or component shorted to ground
Signal or component shorted to
B+
Signal or component missing (open circuit)
The OBD
II system monitors all emission control systems that
are installed. Emission control systems vary by vehicle model
and year. For example, a vehicle may not be equipped with
secondary air injection, so no secondary air readiness code
would be present.
OBD
II software monitors the following:
Oxygen sensors
Catalysts
Engine misfire
- Fuel tank evaporative control system
Secondary air injection Fuel system
Oxygen sensor monitoring. When driving conditions allow,
response rate and switching time of each oxygen sensor is
monitored. The oxygen sensor heater function is also
monitored. The OBD
II system differentiates between
precataylst and post-catalyst oxygen sensors and reads each
one individually. In order
forthe oxygen sensor to be
effectively monitored, the system must be in closed loop
operation.