Start BMW 540i 1998 E39 Workshop Manual

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300-6
/Suspension, Steering and Brakes - General
Rear suspension sedan models
Coil spring
Strut
-
'01 arm
Sport Wagon models
In order to provide a wide, ilat iloor in the cargo compartment,
the rear suspension on the Sport Wagon is unique to itself.
The shoclcabsorber is attached diagonally between the lower
swing arm and a mounting bracket on the subframe. The
spring on each side is mounted between a perch at the top
oi
the wheel bearing carrier and the bottom of the cargo com-
partment floor.
Starting with
1999 Sporl Wagon models, a self-leveling air
suspension system with electronic height control (EHC) was introduced. The system is standard on
V-8 models and op-
tional on 6-cylinder models.
On models fitted with electronic height control (EHC) rear
suspension, the standard coil springs are replaced by air
springs. Air pressure in the air springs is automatically con-
trolled by the
EHC system to compensate for ride height and
load variations.

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Suspension, Steering and Brakes - ~enerail
The main components of the system are the wheel speed
(pulse) sensors, the
ABSIASC or ABSIDSC control module,
and the hydraulic control unit.
Traction control also comes into operation during decelera-
tion. Decelerating on snowy or icy road surfaces can lead to
rear wheel slip. If a rear wheel starts to drag or lock up, the
ASC system can limit the problem by adjusting throttle, fuel
injection and ignition timing.
4 A switch (arrow) on the center console is used to toggle the
ASC on or off.
NOJE-
Even with the ASC system turned off, if the ASC control mod-
ule senses a difference in wheel speed (one wheel spinning)
the
ASC system applies modulated braling force to the slip-
ping wheel until traction is regained. There is no override of
fuelinjection function.
The ASC system is designed to be maintenance free. There
are no adjustments that can be made. Repair and trouble-
shooting of the ASC system requires special test equipment
and knowledge and should be performed only by an autho-
rized
BMW dealer.
ABSIASC traction
I 1.
control system
Wheel speed sensor
Wheel speed pulse wheel
Brake disk
Brake caliper
ABSIASC hydraulic unit
Brake master cylinder
Pedal operated throttle valve
ASC controlled throttle valve
Engine control module (ECM)
Accelerator pedal
ABSlASC control module

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I Steering and Wheel Alignment
This repair group covers steering wheel and column removal
and steering system service, including wheel alignment infor-
mation.
NOTE-
Ignition loclc cylinder replacement is covered in this sec-
tion.
a For information on steering column mounted switches, in-
cluding the ignition switch, see
612 Switches.
Special tools
Some special tools are necessary to carry out the repairs and
adjustments required for steering service and wheel align-
ment. Be sure to read the procedures through before starting
work on the vehicle.
4 Steering shafl retaining ring installation tool
(Tool No. BMW 32
1 090)
4 Bail joint removal tool
(Tool No. BMW 32
1 190)
4 Pitman arm removal tool
(Tool No. BMW 32 2
000)
4 Inner tie rod removal tool
(Tool No. BMW 32 2
110)

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-
-steering and wheel -. Alignment I
< Hand tighten rear suppoll nut (arrow) against mounting
bracket.
Install rear mounting nut and tighten.
Do not over-torque banjo bolts.
* Fill and bleed power steering system as described later.
Tightening torques
Hydraulic lines to steering pump (banjo bolts)
a MlO 12 Nm (9 ft-lb)
. M14 35 Nm (26 ft-lb)
MI6 40 Nm (30 ft-lb)
. MI8 45 Nm (33 ft-lb)
Pump
brackets to engine block 25 Nm (18 ft-lb)
Rear pump support stud to pump housing
22 Nm (16 ft-lb)
Power steering system, bleeding and filling
- With engine off, fill power steering fluid reservoir with clean
fluid. Fill level to MAX
mark on dip stick.
- Start engine. Turn steering wheel twice to left lock and right I
lock.
- Recheck fluid level with engine off. Fill to MAX.

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340-8
1 Brakes
Brake bleeding is usually done for one of two reasons: either
to replace old brake fluid as part of routine maintenance or to
expel trapped air in the system that resulted
from opening the
brake hydraulic system during repairs.
Read the
Warnings listed below before beginning the bleed-
ing procedure an on any
E39 car. If air enters the ACS or DSC
hydraulic unit, the factory BMW Service Tester MUST be
used in conjunction with a bralte pressure bleeder before the
vehicle is driven.
The BMW
ServiceTester (DISpluslGT1iMoDiC) must be
used to bleed the braltes if:
Any hydraulic brake system components are replaced, in-
cluding bralte lines.
Air has enter the
ABSIASC or ABSlDSC hydraulic unit.
WARNING -
* The ASC and DSC systems use electronic controls and a
sophisticated hydraulic unit Once air enters the hydraulic
unit, it is very difficult to remove using traditional methods.
For this reason, pressure
brake bleeding should be done
in conjunction with the BMW
Sewice Tester (DIS-
plus/GTl/MoDiC). The tester electrically cycles the hy-
draulic unit solenoids in the hydraulic unit while
pressurized brake fluid is forced through the system.
When flushing the brake fluid from the system, use ex-
treme care to not let the
brale fluid reservoir run dry If
air enters the hydraulic unit, the BMW Service Tester
MUST be used to bleed the brale system before the
vehicle is driven.
Always use new brake fluid from an unopened container. It is
important to bleed the entire system when any part of the hy-
draulic system has been opened. Be sure to have the special
equipment needed before beginning the job.
When bleeding the
braltes, start atthe wheel farthest from the
master cylinder and progress in the following order:
right rear brake
left rear brake
* right front brake
left front brake

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Brakes
Brakes, bleeding
The procedure below requires a BMW Service Tester (DIS-
pluslGTl/MoDiC).
- Determine type of traction control (ASC, DSC with precharge
pump, DSC without precharge pump). Be sure to use correct
specification brake fluid, according to application table below.
Brake fluid applications
ABS I ASC and ABS / DSC models DOT 4 brake fluid
with precharge pump (to 911998)
ABS I DSC models without precharge DOT 4 low viscosity
pump (911998 and later) brake
fluid
< Remove left side interior ventilation microfilter housing:
Remove upper cover and microfilter loclting clip
(A).
Release locking clamp (B), and rotate air tube in direction
of arrow to remove.
Disconnect wiring harness from hood switch
(C).
Release filter body mounting clamp (D) and remove lower
microfilter housing.
- Top off bralte fluid in reservoir and connect BMW Service
Tester to
20 pin Data Link Connector (DLC) under hood or 16
pin
DLCIOBD I1 connector under dash.
- Call up service function Bleeding ABS / ASC or service func-
tion Bleeding ABS
/ DSC, depending on installed system.
- Fill pressure bleeding device with the correct brake fluid and
connect to brake fluid reservoir and apply pressurize.
Do not exceed a pressure of
2 bar (29 psi) when pressure
bleeding the
brake system. Excessive pressure will damage
4 Starting at right rear wheel, connect bleed hose and fluid re-
ceptacle to bleeder screw (arrow).
CA UTlON-
Bleeder hose must always remain submersed in clean brake
fluid whenever the bleeder valve is open.

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340-1 5
Brakes
- Remainder of installation is reverse of removal.
- Clean brake caliper mounting bolts (7 mm Allen). Replace
ones which are not in perfect condition. Do not grease.
Top up brake fluid to MAX marking.
- Before driving car, pump bralte pedal several times so that
brake pads contact brake rotors.
Check that brake fluid level is correct. Top up if necessary.
Hold ignition key for at least
30 seconds in accessory po-
sition without starting engine. This clears any fault codes in
memory and turns off brake pad warning light.
Tightening torques Brake caliper to pad carrier
(7 mm Allen)
Front caliper
30 Nm (22 It-lb)
- Rear caliper 28 Nm (21 It-lb)
Road wheel to hub
120i 10 Nm (89i7 ft-lb)
Brake rotors, removing and installing
- Raise car and remove wheels
WARNING-
Male sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands beneath structural
chassis points. Do not place jack stands under suspension
parts.
Remove brake caliper carrier bolts (arrows). Suspend brake
caliper from chassis using stiff wire.
NOTE-
Hydraulic brake line remains connected.
4 Remove bralte rotor mounting screw (arrow) and remove ro-
tor.
- Inspect rotor for cracks, signs of overheating and scoring.
- Minimum allowable thickness (MIN TH) is stamped on rotor
hub. Measure rotor braking surface with a micrometer at
eight to ten different points and use the smallest measure-
ment. Compare to specifications in table below.
- If rotor does not pass minimum thickness requirements or is
damaged, replace rotor.

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340-31
Brakes
ABS 1 traction electronic control module
(1 997 -1 998 models)
4 The traction control electronic control module in 1997- 1998
models is located to the left of the glove compartment.
NOTE-
In both ASC and early DSC systems this location is used for
the electronic control unit.
- Before removing the traction control electronic module, read
any fault codes in memory.
ABS I DSC control module
(1 999 - 2002 models)
The DSC electronic control unit in 1999 and later models
(from 911998) is bolted to the DSC hydraulic unit in the right
rear of the engine compartment.
- Before removing the traction control electronic module, read
any fault codes in memory.
- Install electronic control unit using new screws.
Tightening torque
DSC electronic control unit to 2.9 Nrn (26 in-lb)
hydraulic
unit (use new screws)
- Code newly installed module using either DIS or MoDiC.
- Adjust steering angle sensor using menu item Service func-
tion in
DIS or MoDiC.
ABS I traction control hydraulic unit,
removing and installing
WARNING -
E39 cars require special BMWsewice equipment to properly
bleed the brakes. Removal of the hydraulic unit is not recom-
mended unless this equipment is available. For safety rea-
sons, the
brake system on cars with ABS must be bled using
the procedures described in this repair group.
NOTE-
Before starting this procedure, read control module mem-
ory and print
out diagnostic record.
DSC system: Adjust steering angle sensor using
either
DISplus, GTI, or MoDiC. After completing work, function
test control module.

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400-8
Body-General
Airbags
Front airbags, s~de a~rbags, pyrotechnic seat belt tensioners
and the Battery Safety Terminal (BST) are integrated into the
Supplemental Restraint System (SRS) and its variants.
NOTE-
The BMW SRS system is called Multiple Restra~nt System
(MRS). Over the years,
E39 cars were equipped with MRS,
MRS
11, MRS 111. Each version offers varied features and im-
provements over the previous system.
< As many as 8 airbags may be installed in E39 cars, depend-
ing on model and MRS version.
The front
airbags operate without sodium azide propellant,
widely considered an irritant when an
airbag is deployed.
Starting with
1999 models. "smart"front passenger and driver
airbags were installed. These are of the dual-threshold, dual
stage design, including a
sensorto help prevent the unneces-
sary deployment of the passenger side
airbag if the seat is un-
occupied.
MRS control Depend~ng on options chosen, one airbag may be installed in module each door of the sedan and Sport Wagon models, protecting
passengers against
s~de impacts.
Head Protection System (ITS)
airbags strelch diagonally
across the tops of the front doors.
Airbag deployment automatically triggers fuel shutoff, turns
on the hazard and interior lights, and unlocks the doors.
- -
WARNING -
Airbags are inflated by an explosive device. Handled im-
properly or without adequate safeguards,
airbag units can
be very dangerous. Special precautions must be observed
prior to any worlc at or near any of the airbags. See
721 Air-
bag System (SRS).
Always disconnect the battery and cover the negative
(-) battery terminal with an insulator before starting di-
agnostic, troubleshooting or service work on cars fitted
with SRS, and before doing any welding on the
car.

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400-9
Body-General
Battery safety terminal
(BST)
4 Starting with 1999 models (9198 production and later), a py-
rotechnic (explosive charge) device automatically discon-
nects the battery positive terminal during impacts. Key
features,
like power windows and door locks, remain opera-
tional.
Security
Electronic immobilization (EWS)
Ignition key transponder signal All
E39 vehicles incorporate an electronic immobilization sys-
tem known as EWS. This svstem uses a wireless comrnuni-
cation link between a transponder chip in the ignition key and
the ring antenna surrounding the ignition switch. The EWS
control module blocks the starting of the vehicle unless the
correct coded ignition key is used.
NOTE-
Electronic immobilization is sometimes referred to as the
driveaway protection system.
Antitheft alarm (DWA)
This is adealer-installed option for which the E39 vehicles are
factory-wired. When armed, the system monitors door
loci(
contacts and trunk and engine hood locks and sounds a siren
if it detects tampering.
E39 interiors have a unique character, with a combination
of
sporty features and innovativedesign. All body versions were
made in a wide choice of interior and exterior colors. New col-
ors with matching leather or leatherette upholstery were intro-
duced for each model year.
Driving
comfort is enhanced by power steering, tilt steering
wheel, height-adjustable front seats, and electrically adjust-
able and heated rear-view mirrors. Inside the car there are
reading lights at four seating positions.