2000 BMW 528i Ignition

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130-1 0
Fuel Injection
Remove MAF sensor:
Release clips from air filter housing
(A).
Disconnect harness connector (B).
Loosen intake boot clamp (C) and remove MAF sensor.
Note large sealing O-rings.
Installation is reverse of removal.
No adjustment to MAF sensor is possible.
Check intake hoses for cracks and vacuum leaks.
Engine coolant temperature (ECT) sensor,
testing and replacing
R
1 -4 The ECT sensor is located below cylinder 1 intake port
The ECT sensor is a dual temperature sensor. One circuit
provides coolant temperature information to the ECM while
the other circuit provides coolant temperature information to
the instrument cluster.
The ECM determines the correct ignition timing and
airlfuel
mixture required for the engine by monitoring an applied volt-
age
(5 vdc) to the sensor. The voltage drop across the sensor
varies as the coolant temperature (sensor resistance) chang-
es.
NOTE-
The ECT sensor is an NTC (negative temperature coeffi-
cient) type sensor. in other words, as the temperature rises,
resistance through the sensor decreases.
If the ETC sensor input is faulty or non-plausible, the MIL is il-
luminated when
OED II fault criteria are exceeded. The ECM
assumes asubstitute value
(80°C1 176°F) to maintainengine
operation. The ignition timing is set to a
conse~ativelsafe ba-
sic setting.
- Check ECT sensor resistance using a multimeter at sensor
terminals.
-
WARNING -
Due to risk of personal injury, be sure the engine is cold be-
fore disconnecting or reconnecting ECT sensor.
ECT sensor resistance @ 20" C (68°F) 2.2 - 2.7
Temperature gauge sensor resistance @ 20°C (~B"F)( 6.7 k

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Fuel Injection
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Remove engine coolant temperature sensor:
Unclip crankcase vent hose
(C) from cylinder head cover.
Remove plastic cover
(6) from atop intake manifold run-
ners.
Working under front of intake manifold, disconnect ECT
harness.
Unscrew ECT sensor
(C) from cylinder head.
Installation is reverse of removal:
Use new copper sealing washers when installing sensor.
Replace any engine coolant lost.
Tightening torque
Temperature sensor to cylinder head
13 Nm (10 it-lb)
Intake air temperature ([AT) sensor,
testing and replacing
4 The intake air temperature (IAT) sensor (arrow) signal is
used by the ECM to monitor intake air temperature for fuel
and
igntion adaptation. The sensor is .ocared in rne 'ntane
man:lold behind the throttle housng.
The ECM monitors an applied voltage (5 vdc) to the sensor
The voltage drop across the sensor varies as the intake air
temperature (sensor resistance) changes.
NOJE-
The IATsensor is an NTC (negative temperature coefficient)
type sensor. In other words, as the temperature rises, resis-
tance through the sensor decreases.
If the IAT sensor input is implausible, a
fault code is set.The
MIL is illuminated when OED II fault criteria are exceeded.
The ECM then operates the engine using only the engine
coolant temperature (ECT) sensor input.
The intake air temperature sensor can be tested using a
mul-
timeter across its terminals:
/ IAT sensor resistance @ 20" C (68°F) / 2.2 - 2.7 lkCk
~ -- ~~ -
CAUTION--
Be sure ignition is
OFFbefore disconnecting or reconnecting
DME system components.

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130-1 2
Fuel Injection
- Disconnect intake air boot from throttle housing. Unbolt throt-
tle housing and lay aside. It is not necessary to disconnect
throttle cable or electrical harness connectors from throttle housing.
- Remove electrical harness connector from IAT sensor.
- Unclip temperature sensor and remove from intake manifold.
- Installation is reverse of removal. Use a new gasket at throttle
housing.
Throttle position sensor (TPS),
testing and replacing
4 The throttle position sensor (arrow) is located on top of the
throttle valve housing and provides the ECM with a voltage
value that represents throttle position (angle) and rate of
movement.
TheTPS is non-adjustable. If the throttle position sensor is re-
placed, the previous 'learned' TPS settings must be cleared
from the ECM using a BMW-compatible scan tool.
If the throttle position sensor signal is defective, afault code is
stored and the
MILis illuminated when OBD II fault criteria are
exceeded. The ECM still operates the engine using the mass
air flow
(MAF) sensor and engine rpm inputs.
- Check throttle position sensor function by disconnecting har-
ness connector and checking continuity across terminals. If
test results are incorrect,
replace throttle position sensor. The
sensor is non-adjustable.
Throttle
~osition sensor testina values -
Terminals Test
values
1 and ground in harness 5 vdc (approx.)
connector, ltey on
1 and 3 at sensor 4.0 itR(appr0x.)
1 and 2 at sensor Throttle
plate rotated from idle to
lull throttle, continuously variable
from 1.0
- 4.0 1tR
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME svstem components. r

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130-1 3
Fuel Injection I
< Unplug harness connector (arrow) from sensor.
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
NOTE-
Do not confuse the throttle position sensor on the main Nirot-
tle body with the throttle position switch on the secondary
throttle body, where applicable.
- Remove two mounting screws holding sensor to throttle
housing.
- Installation is reverse of removal. Clear adaptation settings
from ECM using BMW-compatible scan tool.
NOTE-
Poor idle quality may be noticeable for a period if the adapta-
tion settings are not cleared after installing new TPS.
ldle speed control valve,
checking and replacing
The idle speed control valve regulates idle speed by redirect-
inq airaround the throttlevalve.The idlespeed control valve is
mounted on the underside of the intake manifold adjacent to
the dipstick tube bracket. Accessing the valve is best accom-
plished by first removing the air filter housing and the throttle
body assembly.
The valve issupplied with
batteryvoltagefrom the ECM relay.
The idle speed control valve incorporates a two-coil rotary ac-
tuator. The ground sides of each coil are pulsed
sirnulta-
neously by the ECM. The duty cycle of each circuit is varied to
achieve the required idle speed.
Afaulty ldle speed control valve sets afault code and the MIL
is illuminated when
OED II fault criteria are exceeded.
Before checking the idle speed control valve, confirm that the
throttle position sensor is working correctly.
- With engine running, check that idle speed control valve is
buzzing.
- Turn on AIC system or shift transmission into drive. ldle
should remain steady or increase slightly.

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Fuel Injection
- If idle speed valve is not buzzing, or if idle decreases when
AIC is turned on, stop engine and disconnect harness con-
nector from idle speed valve.
connector
CAUTION-
Be sure ignition is OFFbefore disconnecting or reconnecting
DME system components.
Checlc resistance of valve across valve terminals.
Idle speed control valve resistance
Terminals
1 and 2 20 i-2Q
Terminals 2 and 3 20 C2Q
Terminals 1 and 3 40 C4Q
The idle speed control valve is mounted under the intake
manifold. Accessing the valve is best accomplished by first
removing the air filter housing and the throttle housing.
< Disconnect intake air boot from throttle housing. Unbolt throt-
tle body and lay aside. Do not disconnect throttle cable or
electrical harness connectors to throttle body.
NOTE-
For additional worlcing room, unfasten and lift out the com.
plete air filter housing.
- Working under intake manifold, disconnect electrical harness
connector from idle speed control valve.
Unbolt dipstick tube
bracket (A) from intalte manifold.
- Remove two bolts (B) retaining idle speed control valve to un-
derside of intalte manifold. Remove valve from intalte mani-
fold. Remove hose clamp and disconnect hose.
- Installation is reverse of removal. Use new gaskets when in-
stalling.

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Fuel injectors, checking and replacing
The fuel injectors are electronically controlled solenoid valves
that provide precisely metered and atomized fuel into the en-
gine intake ports.
The injectors receive voltage from the ECM relay. The ECM
controls the opening by activating the ground circuit
forthe in-
jector valve solenoids. The ECM varies the duration (in milli-
seconds) of "opening" time to regulate the
airlfuel ratio.
For a quick
check of the injectors, run the engine and touch
each injector with a screwdriver or stethoscope. You should
feel a vibration or hear a buzzing
Remove fuel injection harness from injectors by unclipping
locking clip at each injector. Lift harness off injectors.
CA U JIOG
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Use a multimeter to test injector coil resistance between in-
jector terminals.
l~uel injector coil resistance 16R at 20" C (68" F)
Disconnect negative
(-) battery cable
CAUTIOG
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven
in 001 General Warnings and Cau-
tions.
4 Remove plastic trim plugs (arrows) and fasteners, then re.
move cover from above fuel injectors.
- Disconnect vacuum line from fuel pressure regulator.
- Remove wiring harness duct mounting fasteners.

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130-1 8
1 Fuel injection Secondary air injection
1. Secondary air pump (in right
front wheel housing)
2. Secondary air vacuum vent
valve solenoid (on intake mani-
fold)
3. Secondary air check valve
4. Intake manifold
5. Exhaust manifolds
6. Diverter valve (at exhaust mani-
fold)
Engine control module (ECM),
removing and installing
The ECM uses stored functions and processing programs to
process the input signals from the sensors. These input sig-
nals are used to calculate the control (output) signals to the
actuators
(e.g., ignition coils, injectors).
NOTE-
Consult an authorized BMW dealer before replacing the
ECM.
- Disconnect negative (-) battery cable. Wait approximately
one minute.
Prior to disconnecting the
battely, read the battery discon-
nection cautions in
001 General Warnings and Cautions.
Access engine control module (ECM):
Release interior ventilation filter cover latch
(A) and re-
move cover.
Release plastic locking tab
(B).
Rotate air duct inward (arrow) to unloclc from bulk head
and remove duct.
Release spring lock
(C) to remove lower filter housing.
Slide filter housing away from inner fender to remove.
- Remove electrical box (E-box) cover fasteners and remove
cover.
- If testing ECM or connected components, use breakout box
to allow tests to be made with connector attached to the
ECM. This prevents damage to small terminals in connector.

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Fuel Injection I
- As an alternative, harness connector housing can be sepa-
rated so that electrical
checlts can be made from backof con-
nector.
4 If replacing ECM, disconnect control module harness con-
nector (arrow) by releasing fastener and pivoting connector
up and
off ECM.
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
- Remove ECM from retaining brackets and lift off holder.
- Installation is reverse of removal.
- Before attempting to start engine, use BMW service tester
DISplus, MoDiC, GTI or equivalent:
- Code replacement ECM with application information (i.e.
engine code, transmission type, etc.).
Align ECM to EWS (electronic immobilizer).
Siemens MS 41.1 ECM pin assignments
ECM pin assignments are given in Table b. For engine man-
agement system schematics, see ELE Electrical Wiring
Di-
agrams.
CAUTION-
a Always wait at least one minute after turning off the ignition
before removing the connector from the
ECM. If the con-
nector is removed before this time, residual power
in the
system relay may damage the
ECM.
Always connect or disconnect the control module con-
nector and meter probes with the ignition
off
When malting checks at the ECM itself, a breakout box
should be used to allow tests to be made with the connector
attached to the ECM. This also prevents damage to the small
terminals in the connector. As an alternative, the harness
connector housing can be separated so that electrical checlts
can be made from the back of the connector.
Table b. Siemens MS
41.1 ECM pin assignments
Pin
1
2
3
4
Signal
output
output
output
qround Componenfffunction
Ignition coil control, cyl. 2
Ignition coil control, cyl. 4
ignition coil control, cyl. 6
Ground Notes
Primary signal,
ignition
coil 2
Primary signal, ignition coil 4
Primary signal, ignition coil 6
Ground