Wiring BMW 540i 1997 E39 Repair Manual

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170-5
Radiator and Cooling System
Fan switch calibration (M52, M62 engine)
coniprairoi OUt rlgnal
Auto. ciimilte ~ontioi inpuls via CAN bus
Electric fan activation:
Low speed
91°C (196°F)
High speed 104' C (21 9' F)
< In models manufactured after 911998 (M52 TU engine, M54
engine.
M62 TU engine), the electric cooling fan is controlled
by the engine control module (ECM) via the output final
stage.
The output final stage is mounted on the fan housing, next to
the fan motor. The fan is operated using a pulse width modu-
lated signal. Fan circuit wiring is protected by a 50-amp fuse.
Electric fan activation is based on the following inputs to the
ECM:
Radiator outlet temperature
Calculated catalytic converter temperature
Vehicle speed
* Battery voltage
Calculated
A/C pressure
When the vehicle is first started, the ECM activates the elec-
tric fan briefly at 20% of its maximum speed, then switches
off. This is for diagnostic monitoring. The voltage generated
by the fan when it slows down (acting as a generator) must
match the stored rpm values in the fan output stage toconfirm
that the fan is operating correctly.
NOTE-
If the ECM fault memory indicates a cooling fan fault, check
that the fan is not seized and that it spins freely.
When
A/C is switched ON, the electric fan is not immedi-
ately turned on.
After the engine is switched
OFF the fan may continue to
run at varying speeds for up to 10 minutes, based on cal-
culated catalyst temperature.
Transmission fluid heat exchanger
Automatic transmission fluid lines circulate transmission fluid
(ATF) to and from a heat exchanger at the radiator.
All 6-cylinder
models andV-8 models produced to 911998 are
equipped with a transmission cooler located in a cooling cas-
sette in front of the radiator.

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170-1 0
I Radiator and Cooling System
Combustion chamber leak test
- If you suspect that combustion chamber pressure is leaking
into the cooling system past the cylinder head gasket, use an
exhaust gas analyzer to test the vapors rising from the cool-
ant at the expansion tank.
CAUTIO&
Use an extension tube above the reservoir neclc to main-
tain distance between the top of the coolant and the gas
analyzer
nozzle. The gas analyzer is easily damaged if it is
allowed to inhale liquid coolant.
* While running engine to checlc for causes of overheat-
ing, observe coolant temperature carefully in order to
avoid engine damage.
Thermostat
If the engine overheats or runs too cool and no other cooling
system tests indicate trouble, the thermostat may be faulty.
In
V-8 models and 6-cvlinder models nroduced afler 911 998
(M52TU or M54 eng'ne), rheelecrricaily heated rhermostal IS
mon tored by [he OBD II diagnostlc software The fault may ic
in the DME software or hardware, or it may lie in the wiring to
the thermostat. See
OED On-Board Diagnostics.
Coolant, draining and filling
(6-cylinder models)
WARNING -
Allow the cooling system to cool before opening or draining
the cooling system.
- Raise front of car 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 floor jack is not adequate support.
- Remove splash shield from under engine.
4 Loosen radiator bleed screw at top radiator fitting (arrow).
- Remove cap from radiator expansion tank. Set temperature
controls to
full warm.
gallon pail underneath radiator.

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21 0-7
Clutch
- Remove brake fluid reservoir cap. Using a clean syringe.
remove brake fluid from reservoir to below level of clutch
hydraulic supply hose.
- Detach clutch hydraulic supply hose from brake fluid reser-
voir. Plug reservoir outlet and hose.
4 Remove lower dash trim panel fasteners (A) and (B).
Lower trim panel and disconnect wiring harnesses on back
side of panel.
Remove trim panel.
4 Working under dash, remove clutch master cylinder pushrod
retaining clip (arrow) and pin from clutch pedal.
4 Remove master cylinder mounting bolts (arrows)

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Automatic ~ransmissionl
II I
4 Install engine support across engine bay. Raise and safely
support vehicle.
Make sure the car is stable and
we1 supported at all times.
Use a professional automotive lift
orjaclc stands designed for
CAUTIOI\C
Removal of transmission will cause engine to tip unless en-
gine support is used.
- Remove splash shields from underside of vehicle.
- &cylinder models: Detach front stabilizer bar from stabilizer
bar
links. Swivel stabilizer bar upward.
- Drain ATF from transmission as described earlier.
- Remove exhaust system and exhaust heat shield. See 180
Exhaust System.
- Disconnect driveshaft from transmission and hang to one
side. See
260 Driveshaft.
4 With selector lever in park:
Hold
linkage clamping bolt (A) stationary when loosening
selector lever cable clamping nut
(6).
- Loosen cable clamping nut and remove cable from bracket
(ASS
3252 transmission shown).
- Where applicable, disconnect vehicle speed sensor harness
connector.
4 Disconnect main electrical harness connector(s) from trans-
mission by turning bayonet lock
ring(s) (arrows) counter-
clocltwise.
A4S
310R transmission: Harness connector at right rear of
transmission.
ASS
360R / ASS 390R transmission: Harness connector
(arrow) at right rear of transmission.
ASS 3252 transmission: Two connectors (arrows) on left
side of transmission.
ASS 5602 transmission: Harness connector at right rear of
transmission.
- ASS 4402 transmission: Harness connector at top left rear
of transmission.
- Remove wiring harness from transmission housing

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250-7
Gearshift ~inka~el
Automatic shiftlock, checking function (automatic transmission)
The automatic shiftlock uses an electric solenoid to lock the
selector lever in Park or Neutral. Depressing the foot bralte
with the ignition on energizes the solenoid, allowing the lever
to be moved into a drive gear. The solenoid is energized only
when the engine speed is below 2,500 rpm and the vehicle
speed is below
3 mph (5 kph). The solenoid is mounted in the
right side of the selector lever housing.
... nir r
Shiftlock
4 Automatic shiftlock prevents drive gear selection until brake
pedal is depressed.
With engine running and car stopped, place selector lever
in Park or Neutral.
Without depressing bralte pedal, check that selector lever
is
loclted in position (Parlt or Neutral).
Depress brake pedal firmly. Solenoid should click audibly.
Check that selector lever can now be moved out of
Parlt or
Neutral.
parking
brake on and with extreme caution.
solenoid
0012713
With selector
lever in Park or Neutral and bralte pedal de-
pressed, raise engine above 2,500
rpm. Check that selec-
tor lever cannot be moved out of Park or Neutral.
If any faults are found check the electrical operation of the
shiftloclt solenoid and checlt for wiring faults to or from the
transmission control module (TCM). See
610 Electrical
Component Locations and ELE Electrical Wiring
Dia-
grams.
NOTE-
NOTE-
The solenoidis controlled via the TCM, using brake pedalpo-
sition, engine speed, and road speed as controlling inputs.
The
next test should be performed in an open area with the

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-.- .
/ Driveshaft Driveshaft, removing
CAUTION-
. Be sure the wheels are off the ground before removing the
driveshak Set the parl(ing brake before removing the
driveshaft.
Once the driveshaft has been removed, the vehicle can
roll regardless of whether the transmission is in gear or
not.
The driveshaft is mounted to the transmission and final
drive
with self-locliing nuts. These nuts are designed to
be used only once and should be replaced during reas-
sembly.
Remove complete exhaust system. See
180 Exhaust
System.
- Remove exhaust heat shields.
- Support transmission with transmission jack.
< Loosen transmission mount nuts (arrows) on real
transmission support crossmember.
- Release wiring harness retainers from rear transmission
support crossmember.
< Remove mounting bolts (arrows) for rear transmission sup-
port crossmember. Slide crossmember rearward to remove.
- Matchmark front and rear driveshaft halves to corresponding
transmission output and final drive input flanges.
4 Remove nuts securing driveshaft mounting bolts at transmis-
sion output flange. Counterhold bolts (arrows) at transmis-
sion flex-disc. Discard old nuts.
- Hang driveshaft front section from body using stiff wire.

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260-1 0
/ Driveshaft
Driveshaft, installing
- Prepare CV joint for reinstallation:
Extend joint to limit.
Clean off old grease and fill with fresh grease
Install new seal.
- Bend driveshaft slightly at center universal joint to install
CAUTION-
Do not allow CVjoint seal to become displaced.
- Align matchmarlts on driveshaft to matchmarks on final drive
and transmission flanges.
- Fit constant velocity joint to final drive input flange. Alternate-
ly tighten two opposite nuts to draw constant velocity joint
evenly into the final drive input flange. Once seated, tighten
down remaining nuts.
I CAUTION-
I Do not reuse self-locking nuts. These nuts are designed to be /
I used onlv once. 1
- Insert bolts in front of driveshafl to transmission output
flange. Counterhold each bolt while tightening nut.
CAUTION-
. Do not reuse self-locking nuts. These nuts are designed to
be used only once.
Avoid stressing the flex-disc when torquing the bolts.
Do this by counterholding the bolts and turning the nuts
on the flange side.
- Position center support bearing and install mounting nuts.
Use new self-locking nuts.
- Install heat shields.
- Install rear transmission support crossmember.
- Install exhaust system. See 180 Exhaust System.
Reconnect oxygen sensor wiring harnesses and reattach
wiring harness retainers to rear transmission support
crossrnernber.

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Steering and Wheel ~li~nrnentl
q Pry gently to detach flexible cover from upper trim. Lift off
trim.
< Remove lower dash trim panel fasteners (A) and (B).
Lower trim panel and disconnect wiring harnesses on back
side of panel.
Remove trim panel.
- Installation is reverse of removal.
Ignition switch ring antenna (EWS),
removing and installing
- Remove upper and lower steering column trim as described
earlier.
- Disconnect electrical harness plug from ring antenna.
- Use flat side of BMW special tool 61 3 300 to pry ring antenna
off ignition lock cylinder.
- Installation is reverse of removal.
lgnition lock cylinder, removing and
installing
- Disconnect negative (-) cable from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given
in 001 General Cautions and
Warnings.
- Remove upper and lower steering column trim as described
earlier.

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320-1 5
Steering and Wheel ~li~nmentl
Remove steering shaft coupler clamping bolt (arrow) at base
of column.
Slide lower steering shaft forward to gain access to column
mounting shear bolts.
< Drill steering column mounting shear bolts (arrow) and use
easy-out to remove.
Remove upper steering column mounting bolts
(arrows).
Remove upper steering column.
Disconnect electrical harnesses from steering column
switches.
4 Release lock (A) and pull up on harness connector
connect harness.
Remove wiring harness mounting bolt
(C).
- Remove steering column assembly.
(B) to dis.

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I Steering and Wheel Alignment
- Installation is reverse of removal, noting the following:
Replace shear bolts at steering column mounting bracket.
Tighten until bolt heads shear off.
Make sure
interlock cable snaps into place.
When installing column top trim panel, replace expansion
nut for trim retaining screw.
NOTE-
The steering angle sensor must be coded using a BMW scan
tool if it has been replaced.
A steering angle offset check
must then be carried out using the same
BMW scan tool.
CAUTION-
Check steering system for freedom of movement through en-
tire steering column
adiustment range.
Tightening torques Steering shaft coupler
to steering shaft 25 Nm (18 ft-lb)
(replace bolt)
Steering column to body
22 Nm (16 ft-lb)
Steering column adjustment motors,
removing and installing
Remove lower dash panel mounting fasteners (A) and (B).
- Lower panel and disconnect wiring harness from back side.
- Remove steering column lower trim panel. See Steering col-
umn trim, removing and replacing.
- Disconnect electrical harness from motor.
Remove motor mounting fasteners (arrows)
Slide motor to side and forward to remove.
Installation is reverse of removal.