wiring diagram BMW 540i 1997 E39 Workshop Manual

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YOU are now in Volume I
I
Foreword ................... .. ........................................................................\
.......... v
Index
........................ .. ................................................................ rear of manual
General, 001 General Warnings and Cautions 002 Vehicle Identification and VIN Decoder
Maintenance OiO 020 Maintenance
Engine
100 Engine-General 110 Engine Removal and Installation
113 Cylinder Head Removal and
Installation
116 Cyiinder Head and Valvetrain 117 Camshaft Timing Chain
119 Lubrication System
200 Transmission-General
2 Transmission 210 clutch 230 ManualTransmission
I20 Ignition System
121 Battery, Starter, Alternator
130 Fuel Injection
160 Fuel Tank and Fuel Pump 170 Radiator and Cooling System
180 Exhaust System
240 Automatic Transmission
250 Gearshift Linkage 260 Driveshaft
Suspension, 300 Suspension, Steering and 330 Rear Suspension
Brakes-General 331 Final Drive
Steering and No Front Suspension 340 Brakes
320 Steering and Wheel Alignment
400 Body-General
410 Fenders, Engine Hood 411 Doors
412 Trunk Lid, Tailgate
510 Exterior Trim, Bumpers 512 Door Windows
Equipment 513 Interior Trim
7
Equipment and 720 seat Belts
Accessories 721 Airbag System (SRS)
OBD On-Board Diagnostics
. ............ ..
515 Central Lociting and
Anti-Theft
520 Seats 540 Sunroof
.................................................................... Foreword .............................. .. v
Index ................... .. ................................................................ rear of manual
Electrical
6 system
600 Electrical System-General 620 Instruments
610 Electrical Comoonent Locations 630 Liohts
611 wipers and washers 612 Switches eati in^ and Air Conditioning
Radio
. ........... ........ .........................
Electrical Wiring Diagrams

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01 0-2
General
This section is intended to help the do-it-yourselfer get start-
ed. Tips on workshop practices, basic tools, and a quick refer-
ence guide to emergencies can be found here.
WARNING-
Do not use this manual unless you are familiar with basic
automotive repair procedures and safe workshop
practices.
0 This manual illustrates the worl<shop procedures re-
quired for most service work; it is not a substitute for full
and up-to-date information from the vehicle manufac-
turer or for proper training as an automotive technician.
Note that it is not possible to anticipate all of the ways
or conditions under which vehicles may be serviced or
to provide cautions as to all of the possible hazards that
may result.
MOW TO USE THIS MANUAL
WARNING -
Your common sense and goodjudgement are crucial to safe
and successful service
work. Read procedures through be-
fore starting them. Think about whether the condition of your
cac your level of mechanical skill, or pour level of reading
comprehension might result in or contribute in some way to
an occurrence that might cause you injury, damage your car;
or result in an unsafe repair. If you have doubts for these or
other reasons about your ability to perform safe repair work
on your car; have the work done at an authorized
BMW deal-
er or other qualified shop.
The manual is divided into ten sections:
0 GENERAL, MAINTENANCE
0 I ENGINE
2 TRANSMISSION
3 SUSPENSION, STEERING AND BRAKES
4 BODY
5 BODY EQUIPMENT
6 ELECTRICAL SYSTEM
7 EQUIPMENT AND ACCESSORIES
- ELE ELECTRICAL WIRING DIAGRAMS
OBD ON-BOARD DIAGNOSTICS

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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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Ignition System
This repair group covers component troubleshooting and re-
placement information for the ignition system.
When diagnosing engine management problems, including
on-board diagnostics (OBD
11) fault code analysis, also refer
to these repair groups:
* 130 Fuel Injection
* ELE Electrical Wiring Diagrams
OED On-Board Diagnostics
Special tools
System diagnosis and testing of the ignition system requires
special test equipment.
4 LED test light
(Tool No. Baum
1 1 15)
4 Automotive digital multimeter
4 Primary voltage test harness
(Tool No. BMW 12
7 020)
-
4 Secondary voltage test harness
(Tool No. BMW 12
7 030)

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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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Ignition System
- Turn ignition on and check for battery voltage,
If battery voltage is not present,
checlt wire between termi-
nal
15 and the unloader relay. See ELE Electrical Wiring
Diagrams.
- Turn ignition off.
Remove coil and inspect coil housing for hairline
cracks or
leaking casting material. Replace any
cracked or leaking coil.
NOTE-
A leaky coil may indicate a faulty Engine Control Module
(ECM). Check ECM before installing a new coil.
CAUTION-
Note location of coilground straps before coil removal; rein-
stall in the same location.
Use a multimeter to test:
Coil primary resistance at coil terminals.
Sparlt plug connector resistance.
* Compare results to specification in Table c. lgnition coil
resistance.
Table c. Ignition coil resistance
Coil secondary
resistance
Spark plug connector:
Bosch 1 .O I( ohm t 20%
1.8 ir ohm t 20%
Component
Co~l prlmary
resistance
- Replace ignition coil or sparlt plug connector if resistance
readings do not meet specifications.
4 Remove ignition coil to be tested.
Install
BMW special tool 12 7 030 (A) on coil to be tested.
Connect ground jumper between coil mounting point
(B)
and engine ground point (C).
Clip scope high pick-up lead (D) around ignition lead.
Start engine.
Compare scope pattern with diagrams in Oscilloscope
di-
agnostic diagrams.
NOTE-
When replacing ignition coils, ensure that the replacements
Terminal
1 (-) and 15 (+)
are
from the same manufacturer with the same partlcode
numbers. If individual coils with the correct specifications are
not available. all coils should be
re~laced.
Resistance
0.8 ohms

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I Battery, Starter, Alternator
- Check for battery voltage at terminal 50 of starter motor with
key in start position. If voltage is not present, check wiring be-
tween ignition switch and starter terminal. Check the EWS
system and other inputs that disrupt terminal
56 to the start-
er. See ELE Electrical
Wiring Diagrams. If voltage is
present and no other visible wiring faults can be found, prob-
lem is most likely in starter motor.
Starter, removing and installing
(6-cylinder engine)
The starter is removed from below. Access to starter bolts is
difficult. Be sure to have the proper tools on hand before pro-
ceeding.
NOTE-
Access to the starter wiring is very limited. Forbetteraccess,
it may be necessary to remove the intake manifold.
- Disconnect negative (-) battery cable.
CAUTIOI\C
Prior to disconnecting the battern read the baltery discon-
nection cautions
in OOlGeneral Cautions and Warnings.
Remove complete air filter hous~ng:
Loosen intake duct hose clamp (A) at throttle assembly.
Loosen clamp and remove idle control hose from intake
duct
(B) and disconnect idle speed control valve electrical
harness connector.
Disconnect electrical harness connector
(C) from mass air
flow sensor.
Remove air filter housing mounting screw (D)
Disconnect vent tube
(E).
Loosen air intake duct clamp (F).
Carefully lift air filter housing out of engine bay.
Disconnect throttle cable.
Raise vehicle and support safely.
WARNING-
Make sure the car is stable and well supported at all times.
Use a professional automotive
lift orjack stands designed for
the purpose. A
floorjaclc is not adequate support
- Working underneath car, remove engine splash shield
- Disconnect fuel lines and harness connectors from retaining
brackets, as necessary.

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130-6
Fuel Injection
Fuel supply to the injection system is provided by a high pres-
sure electric pump mounted inside the fuel tank. The pump is
powered via the fuel pump relay. If the relay is faulty, the fuel
pump will not run and the engine will not start.
NOTE-
* Fuel delivery volume and fuel pressure are critical to prop-
er operation. Fuel pressure direcfly influences fuel deliv-
ery
Fuel pump relay, fuel pressure and fuel volume tests are
given in 160 Fuel Tank and Fuel Pump.
Relieving system fuel pressure
The fuel system retains fuel pressure in the system when the
engine is off. To prevent fuel from spraying on a hot engine,
system fuel pressure should be relieved beforedisconnecting
fuel lines. One method is to tightly wrap
ashop towel around a
fuel line fitting and loosen or disconnect the fitting. Cleanli-
ness is essential when working with fuel components. Thor-
oughly clean the unions before disconnecting fuel lines.
When system faults are detected, a diagnostic trouble code
(DTC) is stored in the engine control module (ECM). The MIL
also iiluminates if an emissions-related fault is detected
When faults arise, or if the malfunction indicator lamp (MIL) is
illuminated, begin troubleshooting by connecting BMW ser-
vice tester
DISplus. MoDiC, GTI or equivalent scan tool. The
capabilities of OBD
II software has the potential to save hours
of diagnostic time and to help avoid incorrect component re-
placement and possible damage to system components.
CAUTION-
- The tests in this section may set fault codes (DTCs) in the
ECM and illuminate the
MIL. Affer all testing is completed,
access and clear DJC fault memory using an
OED I1 or
BMW compatible scan tool. See OBD On-Board Diag-
nostics.
0 Only use a digital multimeter for electrical tests.
. Relay positions can vary Be sure to confirm relay posi-
tion by identifying the wiring in the socket using the wir-
ing diagrams found in ELE Electrical Wiring
Diagrams.

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Fuel Injection 1
Working in right rear of engine compartment:
Release interior ventilation filter cover latch
(A) and re-
move cover.
Release plastic locking tab
(6).
Rotate duct inward (arrow) to unlock from bulk head and
remove duct.
Release spring
lock (C) to remove lower iilter housing.
Slide filter housing away from inner fender to remove.
- Remove electrical box (E-box) cover fasteners and remove
cover.
NOTE-
OBD I1 fault memory (including an illuminated MIL) can
only be reset using an electronic scan tool. Removing the
connector from the ECM or disconnecting the battery will
not erase the fault
memory.
The BMW-dedicated 20-pin diagnostic linlc connector
(DLC) is in the right rear of the engine compartment.
The 16-pin OBD
I1 diagnostic connector (arrow) is located
inside the car on the lower left dash panel.
ECM relay, testing
Fuses lor ECM In E-bbx 502130488
4 The engine control module (ECM) relay is energized via the
ECM and supplies battery positive
(B+) power to many of the
engine management components and subsystems.
If this re-
lay is faulty, the engine will not start.
Relay positions can vary. Be sure to confirm relay position by
identifying the wiring in the socket using the wiring diagrams
in
ELE Electrical Wiring Diagrams.
NOTE-
The ECM relay is also referred to as the DME main relay.

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130-8
Fuel Injection
With ignition off, remove main relay (K6300) (arrow) in
E-box.
- With ignition on and relay installed, check for battery voltage
on terminal
2 (87).
4 Check for voltage at terminal 8 (30) on relay socket.
If battery voltage is present, relay has energized and is
functioning correctly.
Gmund from 6L (hot ~4th k~y key in Ern
2I '1
on position)
to
Fuel pump RdiWt Rd from Battery and other system components SOZI~O~~I~Y
If battery voltage is not present and all earlier tests are OK,
relay is faulty and should be replaced.
If
battery voltage is present continue testing.
If battery voltage is not present, check fuse 109 (80-amp
fusible link) under passenger seat carpet. See ELE Elec-
trical Wiring Diagrams.
- Reinstall relay and turn ignition on. Gain access to back side
of relay socket and check for ground on terminal
4 (85).
If ground is present continue testing.
If ground is not present, signal from ECM is missing. Check
NOTE-
If no faults are found during testing but power is not reaching
the
ECM or other components, check the fuses in the fuse
carrier
X8680 in the E-box.
wire
between ECM and relay.