1997 BMW 540i Ele

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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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General
Much of the necessary maintenance and minor repairthat an
automobile will need can be done with ordinary tools. Below
you'll find important information on how to work safely, a dis-
cussion of what tools will be needed and how to use them.
Safety
Although an automobile presents many hazards, common
sense and good equipment can help ensure safety. Many ac-
cidents happen because of carelessness. Pay attention and
stick to the safety rules in this manual.
Lifting the car
4 The proper jacking points should be used to raise the car
safely and avoid damage. The
jack supplied with the car can
only be used at the four side points (arrows) just behind the
front wheels or just in front of the rear wheels.
WARNING-
. Never work under a lifted car unless it is solidly supported
on
jack stands that are intended for that purpose.
When raising the car using a floorjack or hydraulic lift,
carefully position the jack pad to prevent damaging the
car body.
* Watch the jack closely. Male sure it stays stable and
does not shift or tilt.
As the car is raised, it may roll
sliahtlv and the
jack mav shift.
Raising car
- Park car on flat, level surface.
- If changing a tire, loosen lug bolts before raising car. See
Changing
a tire.
Place jack into position.
Malte sure jack is resting on flat, sol-
id surface. Use a board or other support to provide a firm sur-
face for jack, it necessary.
- Raise car slowly while constantly checking position of jack
and car.
- Once car is raised, bloclc wheel that is opposite and farthest
from jack to prevent car from unexpectedly rolling.

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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
Many of the maintenance and repair tasks in this manual call
forthe installation of new parts, orthe use of new gaskets and
other materials when reinstalling parts. Most often, the parts
that will be needed should be on hand before beginning the
job. Read the introductorytext and the complete procedure
to
determine which parts will be needed.
NOTE-
For some biggerjobs, partial disassembly and inspection is
required to determine a complete parts list. Read the proce-
dure carefully and, if necessary, male other arrangements to
get the necessary parts while your car is disassembled.
Genuine BMW parts
Genuine BMW replacement parts from an authorized BMW
dealer are designed and manufactured to the same high stan-
dards as the original parts. They will be the correct material.
manufactured to same specifications, and guaranteed to fit
and work as intended. Most genuine BMW parts carry a limit-
ed warranty.
Many independent repair shops make a point of using genu-
ine
BMW parts, even though they may at times be more ex-
pensive than parts from other sources. They know the value
of doing the job right with ihe right parts. Parts from other
sources can be as good as BMW parts, particularly if manu-
factured by one of
BMW's or~ginal equipment suppliers, but it
is often difficult to know.
BMW is constantly updating and improving their cars, often
malting improvements during a given model year. BMW may
recommend a newer, improved part as a replacement, and
your authorized dealer's parts department will know about it
and provide it. The BMW parts organization is best equipped
to deal with your BMW parts needs.
Non returnable parts
Some parts cannot be returned, even for credit. The best ex-
ample is electrical parts, which are almost universally consid-
ered non returnable. Buy electrical parts carefully, and be as
sure as possible that a replacement is needed, especially for
expensive parts such as electronic control units. It may be
wise to let an authorized BMW dealer or other qualified shop
confirm your diagnosis before replacing an expensive non re-
turnable
Dart.

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BMW dealers are uniquely qualified to provide service for
BMW cars. Their authorized relationship with the large BMW
service organization means that they have access to special
tools and equipment, together with the latest and most accu-
rate repair information.
The BMW dealer's service technicians are highly trained and
very capable. Authorized BMW dealers are committed to sup-
porting the BMW product. On the other hand, there are many
independent shops that provide quality repairwork.
Checking
with other BMW owners for recommendations on service fa-
cilities is good way to learn of reputable BMW shops in your
area.
Most maintenance can be accomplished with a small selec-
tion of tools. Tools range in quality from inexpensive junk,
which may break at first use, to very expensive and
well-
made tools for the professional. The best tools for most do-it-
yourself BMW owners lie somewhere in between.
Many reputable tool manufacturers offer good quality, moder-
ately priced tools with a lifetime guarantee. These are your
best buy. They cost a little more, but they are good quality
tools that will do what
Is expected of them. Sears' Craftsman@
line is one such source of good quality tools.
Some of the repairs covered in this manual require the use of
special tools, such as a custom puller or specialized electrical
test equipment. These special tools are called out in the text
and can be purchased through an authorized BMW dealer.
As an alternative, some special tools mentioned may be pur-
chased from the following tool manufacturers and/or distribu-
tors:
Specialty tool suppliers
Assenmacher Specialty Tools
6440 Odeli Place
Boulder. CO 80301
Baum Tools Unlimited, Inc.
P.O. Box 5867
Sarasota.
FL 34277-5867

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Sockets Socltets are used with a ratchet handle for speed and conve-
nience and can be combined with extensions and universal
joints (swivels) to reach fasteners more easily. The most
common socket drive sizes are
114 inch, 318 inch and 112 inch.
Sockets come in
6 point and 12 point styles. The 6 point offers
a better grip on tight nuts and bolts.
6 mm to 19 mm socltets
are the most needed sizes. Below is a list of typical bolt
diarn-
eters and the corresponding wrench sizes.
Common bolt diameters and wrench sizes
M5 8 rnrn
M6
10 rnm
M8 12rnrnor13rnrn
MI 0 17 rnrn
MI2 19 rnrn
M14 22 mm
Spark plug socket
4 A 518" deep-well socket for sparlt plugs includes a rubber in-
sert to both protect the spark plug from damage and grip it for
easier removal.
Pliers
There are many types of pliers including snap-ring,
needle-
nose, adjustable-joint, slip-joint (Channel-lock@), and locking
(Vice-Grip@) most of which are used for holding irregular ob-
jects, bending, or crimping. Some have special applications.
Needlenose pliers are used for gripping small and poorly ac-
cessible objects, and are useful forwiring and other electrical
work. Locking pliers such as the Vise-Grip@ are useful be-
cause of their tight grip.
Snap-ring and circlip pliers with special tipped jaws are used
to remove and install snap-rings or circlips. Channel-lock@ or
water pump pliers have adjustable jaws that can be quicltly
changed to match the size of the object being held to give
greater leverage,

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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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General
Cars with discharged or dead batteries can be jump-started
using the good battery from another car. See owner's manual
for proper instruction on jump starting. When jump-starling
the engine, always note the following warnings.
4 Lower car. With all wheels on ground, fully tighten nuts in a
WARNING-
* Battery acid (electrolyte) can cause severe burns, and will
damage the
cal; clothing, and you. If electrolyte is spilled,
wash the surface with large quantities of water.
M itgets into
eyes, flush them with water for several minutes and call a
doctor.
B4
5
43
2 BOOIFNG.
Batteries produce explosive and noxious gasses.
Keeps sparks and flames away. Do not smoke near
batteries.
Do notjump-start the engine
ifyou suspect that the bat-
tery is frozen. Trappedgas may explode. Allow the bat-
tery to thaw first.
Do not quick-charge the battery (for boost starting) for
longer than one minute, and do not exceed
16.5 volts
at the battery with the boosting cables attached. Wait at
least one minute before boosting the battery a second
time.
crisscross pattern.
Torque wheel nuts when installing wheel.
Check inflation pressure of spare tire.
Tightening torque
Wheel to wheel hub 120 Nm (89 ft-ib)
Jump starting
Indicator and warning lights
Many vehicle systems are self-monitored for faults while driv-
ing. Generally,
a red warning lamp that comes on during driv-
ing should be considered serious. If you cannot immediately
determine the seriousness of the warning light, stop the vehi-
cle in a safe place and turn the engine off as soon as possible.
Consult the owner's manual for additional information on the
warning lamp and the recommended action.
If the Malfunction Indicator Lamp (MIL)
(Check Engine or Ser-
vice Engine Soon warning light) comes on orflashes, it indi-
cates that an emissions-related fault has occurred. Faults
such as a bad oxygen sensor or a dead fuel injector can
cause the exhaust or evaporative emissions to exceed a
specified limit. When these limits are exceeded, the MIL will
be turned on. The engine can be safety driven with the light
on, although the emission systems should be
checked as
soon as possible. See OBD On-Board Diagnostics for