1997 BMW 540i Schematic

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General
0 GENERAL, MAINTENANCE covers general vehicle infor-
mation
(010 General) as well as the recommended mainte-
nance schedules and service procedures to perform BMW
scheduled maintenance
work (020 Maintenance).
The next seven sections
(1 through 7) are repair based and
organized by three digit repair groups. Most major sections
begin with a GENERAL repair group,
e.g. 100 Engine-Gen-
eral. These "00 (double zero) groups contain descriptive the-
ory of operation and system troubleshooting information. The
remainder of the repair groups within a section contain the
service and repair information. The last two sections contain
detailed electrical wiring schematics and OBD
II scan tool and
diagnostic information.
Warnings, cautions and notes
Throughout this manual are many passages with the head-
ings WARNING, CAUTION, or NOTE. These very important
headings have different meanings.
WARNING-
The text under this heading warns of unsafe practices that
are very
likely to cause injury, either by direct threat to the per-
son(~) performing the work
orby increasedrisl( of accident or
mechanical failure while
drivinq.
CAUTION-
A CAUTION calls attention to importantprecautions to be ob-
senfed during the repair work that will help prevent acciden-
tally damaging the car or its parts.
NOTE-
A NOTE contains helpful information, tips that will help in do-
ing a betterjob and completing it more easily.
Please read every WARNING, CAUTION, AND NOTE in
001
General Warnings and Cautions and as they appear in re-
pair procedures. They are very important. Read them before
you begin any maintenance or repair job.

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. .- -
L
- --
- - -. - -- Lubrication ~~stern
- Remove pressure gauge and reinstall pressure switch with
new sealing washer.
Tightening torque
Oil pressure switch to oil filter housing 27 Nm (20 ft-lb)
If testing shows low oil pressure, one or more of the following
conditions may be indicated:
Worn or faulty oil pump or faulty pump pressure relief valve
Worn or damaged engine bearings
Severe engine wear
Any of these conditions indicate the need for major repairs.
Oil pressure warning system, testing
4 When the ignition is turned on, the oil pressure warning light
comes on. When the engine is started and the oil pressure
rises slightly, the oil pressure switch (arrow) contact opens
and the warning light goes out. Make sure the oil level is cor-
rect before making tests.
- Turn ignition switch on.
- Warning light on instrument panel must light up
- Remove connector from oil pressure switch.
Warning light on instrument panel must go out.
NOTE-
If the light does not go out, the wiring to the switch is most
likely grounded somewhere between the switch terminaland
the warning light See
ELE Electrical Wiring Diagrams for
electrical schematics.
- If warning light does not light when ignition is on, remove con-
nector from oil pressure switch and use a jumper wire to
ground connector terminal to a clean metal surface. The oil
pressure warning light should come on.
NOTE-
If there are two wires to the oil pressure switch, ground the
brown/green wire that carries the signal to the warning light.
- If the warning light comes on, check the switch as described
in the next step. If the warning light does not come on, the
wiring to the instrument cluster or to the light itself is faulty.

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Lnition switch
4 The positive (+) power supply to the ignition coils comes to
the ignition switch via an unloader relay. When the ignition
switch is turned on, the relay closes, to provide voltage to the
ignition coils. The coils are then actuated at the negative side
by the engine control module.
NOTE-
Schematic diagrams shown are for illustrative purposes only.
See ELE Electrical Wiring Diagrams for engine manage-
ment specific wiring information.
WARNING- Do not touch or disconnect any cables from the coils while
the engine is running or being cranked by the starter:
The ignition system produces high voltages that can be
fatal. Avoid contact with exposed terminals. Use ex-
treme caution when
working on a car with the ignition
switched on or the engine running.
* Connect and disconnect the DME system wiring and
test equipment leads only when the ignition is
OFF
Before operating the starter without starting the engine
(for example when
making a compression test), always
disable the ignition.
4 Knock sensors (arrows) monitor the combustion chamber for
engine-damaging knock. Six-cylinder models (shown) use
two sensors with each sensor monitoring three cylinders.
V-
8 models use four sensors, each monitoring two cylinders. If
engine
knock is detected, the ignition point is retarded by the
ECM.
I Ignition advance Ignition timing is electronically mapped and not adjustable.
The ECM uses engine load, engine speed, coolant tempera-
ture, knock detection, and intake air temperature as the basic
inputs for timing control.
A three dimensional map similar to
the one shown is digitally stored in the ECM.
- The initial ignition point is determined by the crankshaft
speed sensor during cranking. Once the engine is running.
timing is continually adjusted based on operating conditions.

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Fuel Injection I
- As an alternative, harness connector housing can be sepa-
rated so that electrical
checlts can be made from backof con-
nector.
4 If replacing ECM, disconnect control module harness con-
nector (arrow) by releasing fastener and pivoting connector
up and
off ECM.
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
- Remove ECM from retaining brackets and lift off holder.
- Installation is reverse of removal.
- Before attempting to start engine, use BMW service tester
DISplus, MoDiC, GTI or equivalent:
- Code replacement ECM with application information (i.e.
engine code, transmission type, etc.).
Align ECM to EWS (electronic immobilizer).
Siemens MS 41.1 ECM pin assignments
ECM pin assignments are given in Table b. For engine man-
agement system schematics, see ELE Electrical Wiring
Di-
agrams.
CAUTION-
a Always wait at least one minute after turning off the ignition
before removing the connector from the
ECM. If the con-
nector is removed before this time, residual power
in the
system relay may damage the
ECM.
Always connect or disconnect the control module con-
nector and meter probes with the ignition
off
When malting checks at the ECM itself, a breakout box
should be used to allow tests to be made with the connector
attached to the ECM. This also prevents damage to the small
terminals in the connector. As an alternative, the harness
connector housing can be separated so that electrical checlts
can be made from the back of the connector.
Table b. Siemens MS
41.1 ECM pin assignments
Pin
1
2
3
4
Signal
output
output
output
qround Componenfffunction
Ignition coil control, cyl. 2
Ignition coil control, cyl. 4
ignition coil control, cyl. 6
Ground Notes
Primary signal,
ignition
coil 2
Primary signal, ignition coil 4
Primary signal, ignition coil 6
Ground

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. -
Fuel Injection I
Working inside E-box, disconnect ECM harness connector
(arrow) by releasing fastener and pivoting connector up and
off ECM.
CA UTIOW
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Remove ECM from retaining brackets and lift off holder.
Installation is reverse of removal
Before attempting to start engine, use
BMW service tester
DISplus, MoDiC, GTl or equivalent:
* Code replacement ECM with application information (i.e
engine code, transmission type, etc.).
Align ECM to EWS (electronic immobilizer).
Siemens MS 42.0 and MS 43.0
ECM pin assignments
ECM pin assignments are given in Table c. For engine man-
agement system schematics, see
ELE Electrical Wiring Di-
agrams.
/ CAUTIOW I
Al~ays wait at least one mfnule after turning off the ignition
before
remov;ng [he connecror irom rhe ECM. If the con-
nector is removed before this time, residual power
in the
system relay may damage the
ECM.
Always connect or disconnect the control module con-
nector and meter probes with the ignition off.
When making checks at the ECM itself, a
breakout box
should be used to allow tests to be made with the connector
attached to the ECM. This also prevents damage to the small
terminals in the connector. As an alternative, the harness
connector housing can be separated so that electrical checks
can be made from the back of the connector.
Table
c. Siemens MS 42.0 and MS 43.0 ECM pin assignments
Pin
lslgnal l~om~onentlfunction 1 Notes
Connector
X60001 9-pin black
1 loutput I~erminai 15 I Unloeder relay terminal 15
2 I 1 Not used I
3 Not used
4 Ground
Ground Ground
point

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51 5 Central Locking and Anti-Theft
........................... General .51 5.2
Central Locking ................... .51 5.2
General Module
..................... .51 5.2
Central locking inputs and outputs
....... .51 5.3
Doorlocks
........................... 515-5
Trunklock
........................... 515-7
Remote entry (FZV)
.................. .51 5.7
Remote entry (FZV) inputs and outputs ... .51 5.8
Car Memory I Key Memory ............ .51 5.12
Trunk lid soft close (SCA)
............. .51 5.13
SCA subsystem
.................... .51 5.14
........ Tailgate and rear window locks
.51 5.14
Sport Wagon tailgate and rear
window
lock schematic ............... .51 5.15
Door Handles and Locks .......... .51 5.16
Door handle (outer), removing
and installing
....................... .51 5.16
Door latch, removing and installing
..... .51 5.17
Outer door lock cylinder, removing
and installing
....................... .51 5.18
Trunk Lock Assembly ............. 515-1 9
Trunk lock. removing and installing
...... 515-19
Trunk lock striker plate. removing
and installing
....................... 515-20
Tailgate lock. emergency release
....... 515-21
... Electronic Immobilization (EWS) 515-21
EWS variations
..................... 515-22
......... EWS control module. replacing 515-23
Transmitter
1 receiver module .......... 515-23
....................... Ring antenna 515-23
Anti-theft System (DWA) ........... 51 5-24
DWA LED Status
.................... 51 5-24
Tilt sensor
......................... 515-24
Interior protection .................... 51 5-25
Glass breakage sensors
.............. 515-26
Emergency disarming
................ 51 5-26

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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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515-8
/Central Locking and Anti-Theft
The General Module (GM) is connected to the FZV receiver
module (in left rear roof pillar) via K-Bus. Locking and unlock-
ing of doors, trunk or tailgate and convenience closing is car-
ried out by the GM subsystem controlling the door lock,
window and sunroof modules.
The accompanying schematic, Remote entry
(FZV) inputs
and outputs, illustrates the GM remote entry subsystem.
Remote entry (FZV) inputs and outputs
Inputs Outputs