2000 BMW 540i engine control unit wiring

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I Ignition System
Camshaft position sensors
The camshaft position sensors are used by the englne man-
agement system for VANOS control, sequential fuel injection
and knock control.
Intake camshaft position sensor, replacing
(M52,M52 TU
and M54 engines)
- Make certain ignition has been turned off.
- Remove plastic cover from above fuel injectors by prying off
bolt covers and removing cover mounting bolts.
Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow
sensor
(A).
Detach vacuum line at intake boot (B).
Loosen hose clamp at intake boot and detach air duct con-
nections
(C).
* Disconnect cold air duct tube (D).
Remove filter housing mounting screws (E).
- Disconnect harness connector from VANOS solenoid and
unscrew solenoid from VANOS control unit. Be prepared with
shop rags to catch oil released from VANOS unit.
Remove camshaft sensor (arrow) from
left front of cyl~nder
head, next to top of oil filter housing.
Disconnect camshaft sensor harness from under intake
manifold. Prior to removal, attach a stiff piece of wire to the
harness connector end to preserve proper routing of harness
for reinstallation.
Installation is reverse of removal, noting the following:
Use new O-rings when installing sensor and solenoid.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear
ECM fault memory
Tightening torques
-
Intake camshaft sensor to cylinder head 10 Nrn (7 ft-lb)
VANOS solenoid to VANOS control unit 30 Nm (22 ft-lb)

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Fuel Injection Evaporative fuel system pressure leak
diagnosis, overview
(M5.2.1 only)
1998 540i models are equipped with an evaporative fuel sys-
tem pressure leak diagnosis system. The main component of
this system is the leak diagnosis pump (LDP). The function of
the LDP is to pressurize the fuel tank and the evaporative
emission system for the purpose of detecting
leaks. This sys-
tem is capable of detecting a leak as small as 0.5 mm.
The LDP, located in the left rear wheel housing, is a unitized
component that contains the following:
Vacuum chamber. Pneumatic pump chamber.
DME activated vacuum solenoid
Reed switch (provides switched voltage
feedback signal to
ECM).
The vacuum supply line is in the wiring harness from the en-
gine compartment and runs down the driver's side of the vehi-
cle.
The canister vent valve is integrated into the LDP, which is
electrically controlled by the ECM. The canister vent valve is
opened to provide fresh air entry into the fuel system only dur-
ing purge operation.
- Purge operation characteristics:
Off idle through full throttle: purge valve opened by pulse
width modulated (PWM) control of the ECM. PWM duty cy-
cle varies by engine operating conditions
(e.g. warm idle,
purge valve opened slightly; cold
idleldecel with engine
temp
< 67" C, purge valve always closed).

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-- I
I: ... . -. Rear Suspension! -- .- -
Air compressor pump relay, removing and
installing
- Working in cargo compartment, remove spare wheel.
4 Remove air supply pump fasteners (arrows). Turn pump
over.
- Turn relay plug 45" and remove relay.
EHC control module, removing and
installing
The EHC control module is mounted on the right side of the
spare tire
well in the cargo compartment.
- Remove spare tire.
4 Remove electrical components cover (A).
- Release control module wiring harness plug loclting clip (B)
and remove module.
- Installation is reverse of removal.
- After assembly, reset ride height using BMW diagnostic scan
tool DIS.
Air supply unit, removing and installing
CAUTION-
Maintain high levels of cleanliness around air line connec-
tions when disassembling and assembling air suspension
components. Even small dirt particles can cause
leakage in
the pressurized system.
When the airsupply unit is removed for any reason, reset ride
height using BMW scan tools DIS or
MoDiC.
- Remove spare tire.
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