Electrical system BMW 540i 1998 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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001 General Warnings and Cautions
PLEASE READ THESE WARNINGS AND CAUTIONS
BEFORE PROCEEDING
WITH MAINTENANCE AND REPAIR WORK.
WARNINGS-
See also CAUTIONS
- Some repairs may be beyond your capability. If you lack the skills, - Catch draining fuel, oil, or brake fluid in suitable containers. Do
tools and equipment, or a suitable workplace for any procedure
not use
foodor beverage containers that might mislead someone
described in this manual, we suggest you leave such repairs to
into
drinking from them. Store flammable fluids away from fire
an authorized BMW dealer service department or other qualified
hazards. Wipe up spills at once, but do not store the oily rags,
shop. which can ignite and burn spontaneously.
. Do not reuse any fasteners that are worn or deformed. Many fas- Always observe good worRshop practices. Wear qoqqles when
teners are designed to be used only once and become
unreliable you operate machine tools or work with battery acid:kloves or
and mav fail when used a second time. This includes, but is not other
~rotective clothino should be worn whenever the iob re-
limited io, nuts, bolts, washers, self-locking nuts or bolts, clrclips yires' working with harmful substances.
and cotter pins. Always replace these fasteners with new parts.
Greases, lubricants and other automotive chemicals contain toxic
. Never work under a lifted car unless it is solidly supported on
substances, many of which are absorbed directly through the
stands
desiqned for the purpose. Do not supeort a car on cinder
skin. Read the manufacturer's instructions and warninos careful-
blochs, hollow tiles orotherbrops that may drurnbie undercontin-
uous toad. Never work under a car that is supported solely by a
iack. Never work under the car
while the enqine is runninq. - -
If you aregoing to work underacaron the ground, makesure that
the ground is level. Block the wheels to
keep the car from rolling.
Disconnect the battery negative
(-) terminal to prevent others
from starting the car while you are under it.
- Never run the engine unless the work area is well ventilated. Car-
bon monoxide kills.
Rings, bracelets and other jewelry should be removed so that
they cannot cause electrical shorts, get caught in running ma-
chinery, or be crushed by heavy parts.
- Tie long hair behind your head. Do not wear a necktie, a scarf.
loose clothing, or a necklace when you work near machine tools
or running engines. if your hair, clothing, or jewelry were to get
caught in the machinery, severe injury could result.
DO not attempt to
work on your car if you do not feel well. You in-
crease the
danger of injuryto yourseliand others if you are tired,
uDset or have taken medication or anv other substance that mav
keep you from being fully alert.
Illuminate your work area adequately but safely. Use a portable
iy. Use hand and eye protection. Avoid direct skin conGct.
Disconnect the battery negative (-) terminal whenever you work
on the fuel system
orthe electrical system. Do not smokeorwork
near heaters or other fire hazards. Keep an approved fire extin-
guisher handy.
. Friction materials (such as brake pads or shoes or clutch discs)
contain asbestos fibers or other friction materials. Do not create
dust by grinding, sanding, or by cleaning with compressed air.
Avoid breathing dust. Breathing any
friclion material dust can
lead to serious diseases and may result in death.
Batteries
giveoff explosive hydrogen gas during charging. Keep
sparks, lighted matches and open flame away from the top of the
battery. If hydrogen gas escaping from the cap vents is ignited, it
will ignite gas trapped in the cells and cause the battery to ex-
plode.
Connect and disconnect battery cables, jumper cables or a bat-
tery charger only wilh the ignition switched off. Do not disconnect
the battery while the engine is running.
Do not quick-charge the battery (for boost starting) for longer
than one minute. Wait at least one minute before boosting the
battery a second time.
. . safety lighiforworking lnsideor under the car. Make sure the bulb - Do not allow battery charging vollage to exceed 16.5 volts. If the
is enclosed bv a wire caoe. The hot filament of an accidentallv
batten! beoins ~roducina oas or boilino violentiv, reduce the
broken bulb can ignite spilled
fuel, vapors or oil. , - - - charglng rate. ~oostlng a sutfaled battery at a igh charging rate
can cause an
explosion.
-
Continued on next page

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I General Warnings and Cautions
WARNINGS (continued)
. The air conditioning system is filled with chemical refrigerant,
which is hazardous. The AIC system should be serviced only by
trained technicians using approved refrigerant recoverylrecycling
equipment, trained in related safety precautions, and familiar with
regulations governing the discharging and disposal of automotive
chemical refrigerants.
. Do not expose any part of the AIC system to high temperatures
such as open flame. Excessive heat will increase system pres-
sure and may cause the system to burst.
Some aerosol tire inflators are highly flammable. Be extremely
cautious when repairing a tire that may have been inflated using
an aerosol tire inflator. Keep sparks, open flame or other sources
of ignition away
from the tire repair area. Inflate and deflate the
tire at least four
times before breaking the bead from the rim.
Completely remove the tire from the rim before attempting any re-
pair.
Cars covered by this manual are equipped with a supplemental
restraint system (SRS), that automatically deploys
airbags and
pyrotechnic seat belt tensioners
In the event oi a frontal or side
impact. These are explosive devices. Handled improperly or with-
out adequate safeguards, they can be accidently activated and
cause serious injury.
- The ignition system produces high voltages that can be fatal.
Avoid contact with exposed terminals and use extreme care when
working on a car with the engine running or the ignition switched
on.
. Place jack stands only at locations specified by the manufacturer.
The vehicle
illtino iack su~olied with the vehicle is intended fortire -. , . changes only. A heavy duty floor jack should be used lo lift vehicle
before installing
jacl( stands. See 010 General.
- Battery acid (electrolyte) can cause severe burns. Flush contact
area
with water, seek medical attention.
Aerosol cleaners and solvents may contain hazardous or deadly
vapors and are highly flammable. Use only in a well ventilated ar-
ea. Do not use on hot surfaces (engines, brakes, etc.).
Do not remove
coolant reservoir or radiator cap with the engine
hot. Danger of burns and engine damage.
CAUTIONS-
See also WARNINGS
- if you lack the slqills, tools and equipment, or a suitable worl(shop
for any procedure described in this manual, leave such repairs to
an authorized BMW dealer or other qualified shop.
BMW is constantly improving its cars and sometimes these
changes, both in parts and specifications, are made applicable to
earlier models. Therefore, part numbers listed in this manual are
for reference only. Always check with your authorized BMW deal-
er parts department for the latest information.
Before starting a job, make certain that you have all the neces-
sary tools and parts on hand. Read ail the instructions thorough-
ly, and do not attempt shortcuts. Use tools appropriate to the
work and use only replacement parts meeting BMW specifica-
tions.
Use pneumatic and electric tools only to loosen threaded parts
and fasteners. Never use these tools to tighten fasteners, espe-
cially on light alloy parts. Always use a torque wrench to tighten
fasteners to the tightening torque specification listed.
Be mindful of the environment and ecology. Before you drain the
crankcase, find out the proper way to dispose of the
oil. Do not
pour
oil onto the ground, down a drain, or into a stream, pond or
lake. Dispose of waste in accordance with Federal, State and
Local laws.
The control module for the anti-lock brake system
(ABS) cannot
withstand temperatures from a paint-drying booth or a heat
lamp
in excess of 203" F (95°C) and should not be subjected to tem-
peratures in excess of 185°F
(8S°C) for more than two hours.
- Before doing any electrical welding on cars equipped with ABS,
disconnect the battery negative
(-) terminal (ground strap) and
the ABS control module connector.
- Always make sure ignition is off before disconnecting battery.
Label battery cables before disconnecting. On some models, bat-
tery cables are not color coded.
Disconnecting the battery may erase fault code@) stored in control
module memory. Using special BMW diagnoslic equipment, check
lor
iauit codes prior to disconnecting the battery cables. If the mal-
I.mct on ndicator Ignt (MIL) s I. ..minaled. see OBD On-Board
Diaanostics
Tl11s iant is iuenlfted as lne Check Ena~ne oht
(1997-2000 models jor~ervlce Engine Soon light (2061 andlater
models). If any other system iaults have been detected (indicated
by an illuminated warning light), see an authorized BMW dealer.
If a normal
or rapid charger is used to charge battery, the battery
must be disconnected and removed from the vehicle in order to
avoid damaging the vehicle.
- Do not quick-charge the battery (for boost starting) for longer
than one minute. Wait at least one minute before boosting the
battery a second time.
* Connect and disconnect a battery charger only with the battery
charger switched off.
- Sealed or "maintenance free" batteries should be slow-charged
only, at an amperage rate that is approximately 10% of the bat-
tery's ampere-hour (Ah)
rating.
. Do not allow battery charging voltage to exceed 16.5 volts. If the
battery begins producing gas or boiling violently, reduce the
charging rate.
Boosting a sulfated battery at a high charging rate
can cause an explosion.

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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 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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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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.
General
WARNING-
Never run the engine in tile work area unless it is well-ven-
tilated. The exhaust should be vented to the outside. Car-
bon monoxide (CO) in exhaust kills.
Remove all neckties,
scarfs, loose clothing, or jewelry
when working near a running engine or power tools.
Tuck in shirts. Tie long hair and secure it under a cap.
Severe injury can result from these things being
caugiit
in rotating parts.
Remove rings, watches, and bracelets. Aside from the
dangers of moving parts, metallic jewelry conducts
electricity and may cause shorts, sparks, burns, or
damage to the electricalsystem when accidentally con-
tacting the battery or other electrical terminals.
Disconnect the battery negative
(-) cable whenever
working on or near the fuel system or anything that is
electrically powered. Accidental electrical contact may
damage the electrical system or cause a fire.
Fuelis highly flammable. When working around fuel, do
not
smoke or work near heaters or other fire hazards.
Keep an approved fire extinguisher handy.
The fuel system is designed to retain pressure even
when the ignition is off When worlcing with the
fuelsys-
tem, loosen the fuel lines slowly to allow the residual
pressure to dissipate gradually. Take precautions to
avoid spraying fuel.
. Illuminate the worlc area adequately and safely Use a
portable safety light for worlcing inside or under the car.
A fluorescent type
light is best because it gives off less
heat. If using a light with a normal incandescent bulb,
use rough service bulbs to avoid
breakage. The hot fil-
ament of an accidentally broken bulb can ignite spilled
fuel or oil.
Keep sparks, lighted matches, and any open flame
away from the top of the battery. Hydrogen gas
emitted
by the battery is highly flammable. Any nearby source
of ignition may cause the battery to explode.
Never lay
tools or parts in the engine compartment or
on top of the battery. They may
fallinto confinedspaces
and be difficult to retrieve, become caught in belts or
other rotating parts when the engine is started, or
cause electrical shorts and damage to the electrical
system.

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01 0-1 0
General
Electrical testing
Many electrical problems can be understood and solved with
only a little fundamental knowledge of how electrical circuits
function.
Electrical current
only flows in a complete circuit. To operate.
every electrical device in the car requires a complete circuit
including a voltage source and a path to ground. The positive
(+) side of the battery is the original voltage source, and
ground is any return path to the negative
(-) side of the bat-
tery, whether through the wiring harness or the car body. Ex-
cept for portions of the charging system, all electrical current
in the car is direct current (DC) and flows from positive
(+) to
negative
(-).
4 Switches are used to turn components on or off by complet-
ing or interrupting the circuit.
A switch is "open" when the cir-
cuit is interrupted, and "closed" when the circuit is completed.
See
600 Electrical System-General for electrical trouble-
(LW, 1 shooting
Wire repairs
Light bulb
(consumer) ' - Repairs to a wiring harness require special care to make the
repair permanent. The wire ends must be clean.
if frayed or
Car body otherwise damaged, cut off the end and remove enough insu- (ground) i Battery lation to complete the repair. if the wire is too short, splice in a BOZLiEL new piece of wire of the same size and make two connec-
tions.
Use connectors that are designed for the purpose. Crimped
on orsoldered-on connectors are best. Crimp connectors and
special crimping pliers are widely available. If soldering, use
needle nose pliers to hold the wire near the solder joint and
create a "heat dam". This keeps the heat and the solder from
traveling up the wire. Always use a solder made specifically
for electrical
work (rosin core).
NOJE-
Twisting wires together to make a repair is not recommend-
ed. Corrosion and vibration will eventually spoil the connec-
tion and may lead to irreparable damage to sensitive
electronic components.
Insulate the finished connection. Electronics stores can sup-
ply heat-shrinkable insulating tubing that can be placed on to
the wire before connecting, slid over the finished joint, and
shrunic to a tight fit with a heat gun or hair dryer. The next best
alternative is electrical tape. Make sure the wire is clean and
free of
solder flux or other contamination. Wrap the joint tight-
ly to seal out moisture. See
600 Electrical System-General
for more information.

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.
General
Torque wrench
A torque wrench is used to precisely tighten threaded fasten-
ers to a predetermined value. Many of the repair procedures
in this manual include BMW-specified torque values
in New-
ton-meters (Nm) and the equivalent values in foot-pounds
(ft-
Ib).
4 Several types of torque wrenches are available. An inexpen-
sive beam-type (top) is adequate but must be read visually. A
ratchet-type (bottom) can be preset to indicate (click) when
the torque value has been reached. They all do the same job,
but offer different convenience features at different prices.
The most convenient ones have a built-in ratchet, and can be
preset to indicate when a specific torque value has been
reached. Follow the wrench manufacturer's directions
for use
to achieve the greatest accuracy.
A torque wrench with a range up to about 150 Nm (1 10 ft-lb) BOIBFNG has adequate capacity for most of the repairs covered in this
manual. For recommended torque values of
10 Nm orbelow,
the English system equivalent is given in inch-pounds (in-lb).
These small values may be most easily reached using a
torque wrench calibrated in inch-pounds. To convert
inch-
pounds to foot-pounds, divide by 12.
Digital multimeter
4 Many of the electrical tests in this manual call for the mea-
surement of resistance (ohms) or voltage values. For safe
and accurate tests of sensitive electronic component and
systems, a multimeter or digital
volt/ohm meter (DVOM) with
high input impedance (at least
10,000Sr) should be used.
Some meters have automotive functions such as dwell and
pulse width that are useful for troubleshooting ignition and
fuel injection problems.
CAUTIOI\C
Vehicle electronic systems may be damaged by the high cur-
rent draw of a test light with a normal incandescent bulb. As
a general rule, use a high impedance digital multimeter or an
LED test light for all electrical testing.

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Two common causes of driveability problems are incorrect
system voltage and bad grounds.
System voltage
Digital motor electronics (DME) requires that the system (bat-
tery) voltage be maintained within a narrow range of DC volt-
age.
DC voltage levels beyond or below the operating range,
or any
AIC voltage in the electrical system can cause havoc.
When troubleshooting an illuminated MIL, make sure the bat-
tery is fully charged and capable of delivering all its power to
the electrical system. An undercharged battery can amplify
AIC alternator output ripple.
To
make a quick check of the battery charge, measure the
voltage across the battery terminals with all cables attached
and the ignition off.
Afully charged battery will measure 12.6
volts or slightly more, compared to 12.1 5 volts for a battery
with a 25% charge.
The DME system operates at low voltage and current levels,
making it sensitive to small increases in resistance. The elec-
trical system is routinely subjected to corrosion, vibration and
wear, so faults or corrosion in the wiring harness and connec-
tors are not uncommon. Check the battery terminals
forcorro-
sion or loose cable connections. See 121 Battery, Starter,
Alternator for additional information.
If a battery cable connection has no
v~sible faults but is still
suspect, measure the voltage drop across the connection. A
large drop indicates excessive resistance, meaning that the
connection is corroded, dirty, or damaged. Clean or repairthe
connection and retest.
NOTE-
For instructions on conducting a voltage drop test and other
general electrical troubleshooting information, see
600 Elec-
trical System-General.
Visually inspect all wiring, connectors, switches and fuses in
the system. Loose or damaged connectors can cause inter-
mittent problems, especially the small terminals in the ECM
connectors. Disconnect the wiring harness connectors to
check for corrosion, and use electrical cleaning spray to re-
move contaminants.
Main grounds
Good grounds are critical to proper DME operation. If a
ground connection has no visible faults but is still suspect.
measure the voltage drop across the connection. A large volt-
age drop means high resistance. Clean or repair the connec-
tion and retest.
LBuntr.yP~sbhnllcn.can#-AII A,~iltl Rcsrwsd

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100-6
( Engine-General
The main grounds for the fuel and ignition circuits of the DME
system are illustrated below; see 610 Electrical Component
Locations for additional ground and component locations.
4 Ground for engine management system in right rear of en-
gine compartment on E-box bulkhead (arrow).
6-cylinder models: Grounds
for ignition coils (arrows)
4 V-8 models: Grounds for ignition coils, at cylinders 3
(arrow) and 7.
4 Fuel pump ground (arrow) below right tail light in luggage
compartment.
NOTE-
Ground location for sedan shown, wagon models may
differ.