2001 BMW 525i Air sensor

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Fuel Injection
4 Remove electrical harness connector (arrow) from IAT sen-
sor.
CAUTION-
Be sure the ignition switch is in the off position before repiac-
ins the intake temperature sensor.
- Depress loclting clip on side of temperature sensor and pull
straight out of intake manifold.
- Installation is reverse of removal
- Use a new sealing O-ring at base of sensor and lubricate with
assembly lubricant for
ease of installation
MS 42.0 throttle valve assembly, replacing
< The motor driven throttle valve for the MS 42.0 system is re-
- ferred to as MDK (motor driven throttle valve). The MDK unit
is electronically operated to regulate intake air flow by the
ECM.
The
MS 42.0 system uses a throttle cable from the accelera-
tor pedal to the MDK unit. The throttle cable is connected di-
rectly to the integral pedal position sensor
(PWG) in the MDK
unit. This sensor communicates pedal position to the ECM,
which in turn electronically regulates throttle plate position.
The MDK pulley is linked to the throttle shaft by springs to al-
low ASC intervention to override the driver's pedal position.
NO TE -
The MDIC unit is non-adjustable and must be replaced as
a complete unit if found to be faulty.
if replacing the
MDK unit, the adaptation values stored in
the ECM must be clearedand the new unit initialized using
BMW special service tools.
CAUTION-
If the adaptation process is not completed correct& the en-
gine wiii
not start.
- Disconnect battery negative (-) cable in luggage compart-
ment.
CAUTION-
Prior to disconnecting the battern read the battely discon-
nection cautions in
001 General Warnings and Cautions.

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Fuel lniection I
4 Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow
sensor
(A).
Disconnect vacuum line at intake boot (B).
Loosen Intake air duct clamp (C).
Remove filter housing mounting screws
Disconnect air duct and
lift complete air filter housing and
MAF sensor out of engine compartment, pulling it forward
away from throttle housing.
- Pull throttle cable upwards out of rubber retainer and unhoolc
ball end of cable from throttle actuator.
4 Remove nuts and bolts (arrows) retaining wiring harness to
throttle housing.
- Working at throttle housing, turn harness plug counterclock-
wise and remove plug.
4 Working at side of intake manifold, disconnect electrical har-
ness connectors:
Idle control valve (A)
lntalce manifold resonance valve (B)
- Disconnect electrical harness connectors at oil pressure
sender and oil temperature sender at base of oil filter hous-
ing.
CO,l,> ti,, "F"bl,rl,irrm.,-AI ",",>ti

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Fuel Injection
MS 43.0 throttle valve assembly, replacing
The electronic throttle valve assembly forthe MS43.0 system
is referred to as
EDK (electronic throttle valve). There is no
mechanical (cable) link between the accelerator pedal and
the throttle plate.
< The accelerator pedal module (PWG) at the pedal assembly
communicates the pedal position directly to the ECM. The
module provides two variable voltage signals (via two Hail
sensors) to the ECM for pedal position and rate of movement.
NOTE-
The EDK unit is non-adjustable and must be replaced as a
complete unit if found to be faulty
If replacing the
EDK unit, the adaptation values stored in
the
ECM must be cleared and the new unit initialized using
BMW special service tools.
CAUTIOIG
If the adaptation process is not completed correctk the en-
qine will not start
- Disconnect battery negative (-) cable in luggage compart-
ment.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given in
001 General Warnings and Cau-
tions.
< Remove complete air filter housing:
- Disconnect electrical harness connector on mass air flow
sensor
(A).
Disconnect vacuum line at intake boot (6).
Loosen intaite air duct clamp (C).
Remove filter housing mounting screws.
Disconnect air duct and lift complete air filter housing and
MAF sensor out of engine compartment, pulling it forward
away from throttle housing.

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130-38
Fuel Injection
Throttle cable, adjusting
(MS 42.0)
The throttle assembly on MS 42.0 cars uses a throttle cable.
The cable should be adjusted any time it is disconnected or
replaced. This procedure requires the factory scan tool or an
equivalent to read and adjust throttle angle. It is recommend-
ed the procedure be done by an authorized
BMW dealer ser-
vice department
Basic adjustment:
Ensure that at idle (accelerator pedal in rest position) throt-
tle cable has detectable play at throttle lever attaching
point. Play must not exceed maximum allowable.
Adjust by turning knurled adjuster
(arrow) on end of throt-
tle cable sheath at throttle housing.
NOTE-
Faulty throttle adjustment values must be reset using the
BMW service tester
DISplus, MoDiC, GTI or equivalent.
Max.
play at throttle plate lever
ldle speed control valve,
checking and replacing
3 mm (0.125 in)
The Idle speed control valve regulates Idle speed by red~rect-
ing air around the throttle valve. The ldle speed control valve
is mounted
d~rectly above the throttle housing. Accessing the
valve is best accomplished by
flrst removing the air fllter
housing and associated ducting.
Thevalve is supplied with batteryvoltage from the ECM relay.
The idle speed control valve incorporates a two-coil rotary ac-
tuator. The ground sides of each coil are pulsed simulta-
neously by the ECM. The duty cycle of each circuit is varied to
achieve the required idle speed.
A faulty idle speed control valve sets a fault 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.
- 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.

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130-40
Fuel Injection
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.
CAUTION-
Prior to disconnecting the batteg read the battery discon-
nection cautions
in 001 General Warnings and Cautions.
4 Access engine control module (ECM):
Release
interlor ventilation filter cover latch (A) and re-
move cover.
Release plastic loclting tab
(B).
Rotate air duct inward (arrow) to unloclt from bulk head
and remove duct.
Release spring lock
(C) to remove lower filter housing.
Slide
f~lter hous~ng 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 ECM.
This prevents damage to small terminals in connector.
- - As an alternative, harness connector housing can be sepa-
rated so that electrical checks can be made from
back of con-
nector.
4 If replacing ECM, disconnect control module harness con-
nector (arrow) by releasing fastener and pivoting connector
up and off ECM.

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.-
/Fuel Injection
I ' I - I
9 /ln~ut l~oltaqe supply I Fuse carrier, engine electronics
Table
c. Siemens MS 42.0 and MS 43.0 ECM pin assignments (continued) I ' I . I
Connector X60002 24-pin
1 linput IHeater, precatalyst oxygen sensor 1 I Heated oxygen sensor 1 in front of cat. conv.
I I I
18 llnout IHeater, post-catalyst oxygen sensor 2 ]Heated oxygen sensor 2 behind cat. conv.
Notes
Ground connector
Ground connector
B+ terminal
Fuse carrier, engine electronics
Pin
5
6
7
8
I I I
4 loutput l~hrottle valve supply (MS
42.0) I~hrottle valve (MS 42)
Signal
Ground
Ground Input
lnout
19
20 21
22
23
24
Connector
1
2
3
I I I
5 1 lnput ISignal, intake camshaft position sensor /camshaft position sensor 1
Componentlfunction
Ground
Ground
Terminal 30
Voltaae
SUDP~V
input
Ground
Ground
Ground
Input
Ground
X60003 52-pin
Input
Input
~ -
Heater, post-catalyst oxygen sensor 2
Ground, precatalyst oxygen sensor
1
Ground, precatalyst oxygen sensor 2
Ground, post catalyst oxygen sensor
1
ECM (DME main) relay signal activation
Ground, post catalyst oxygen sensor 2
Signal, mass air
flow sensor
Signal, exhaust camshaft sensor
Not used Heated
oxygen sensor 2 behind cat.
conv.
Heated oxygen sensor 1 in front of cat. conv.
Heated oxygen sensor 2 in front of cat. conv.
Heated oxygen sensor
1 behind cat. conv.
ECM
Heated oxygen sensor 2 behind cat. conv.
Hot film mass air flow sensor
Camshaft position sensor

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130-43
Fuel Injection ]
I I I
12 llnput IFeedback signal, engine start /Starter
Table c. Siemens MS 42.0 and MS 43.0 ECM pin assignments (continued)
I I - I
13 Input /I Alternator (generator) Notes
Throttle
valve
Crankshaft position sensor
Throttle valve (MS
42.0)
Throttle valve
Pin
6
7
8
9
10
11
14
15
16
17
18
19
20
I 1- I
23 l~round I~round, intaite air temperature sensor /Intake air temperature sensor
Signal
Output
Input
Input
Input
I I I
Component/function
Not used
Throttle valve supply potentiometer
2
Signal, crankshaft position sensor
Signal,
pedal position sensor 2 (MS 42.0)
Signal, throttle position sensor 1
Not used
Ground
Ground
Input
Ground
Ground
Input
Ground Cranltshaft position sensor
21
24
25
26
27
28
29
30
I 1- I
33 1 input ISignal, cylinder 1 fuel injector /cylinder 1 fuel injector
Ground, throttle position sensor (MS
42.0)
Ground, exhaust camshaftsensor I
Signal, pedal position sensor 1 (MS 42.0)
Ground, mass air flow sensor
Ground, intake camshaft sensor
1
Signal, throttle potentiometer 1
Ground, throttle position sensor
22 loutput I~ignal, intake air temperature Ilntake air temperature sensor
I I - I
Throttle
valve (MS 42.0)
Camshaft position sensor I
Throttle valve (MS
42.0)
Hot film mass air flow sensor
Camshaft position sensor i
Throttle valve
Throttle valve
Ground
Output
Ground Input
Output
Ground
Output
Out~ut
Ground, crankshaft position sensor
Knoclt sensor
31
34
35
36
37
38
39
Signal, coolant temperature sensor
Ground, coolant temperature sensor
Signal,
oil pressure
Signal, engine
oil temperature sensor
Ground, engine oil temperature sensor
Signal, knock sensor
Signal, knock sensor
32 loutput ISignal, ltnock sensor l~nock sensor
40
41
Coolant temperature sensor
Coolant temperature sensor
Oil pressure switch
Oil temperature sensor
Oil temperature sensor
Knoclt sensor
I Output
Input
input
Input
Input
Input
Inout
Signal, knock sensor
Input
Input Signal, cylinder
2 fuel injector
Signal, cylinder
3 fuel injector
Signal, cylinder
4 fuel injector
Signal, cylinder
5 fuel injector
Signal, cylinder
6 fuel injector
Sianai, oil level sensor Cylinder
2 fuel
injector
Cylinder
3 fuel injector
Cylinder
4 fuel injector
Cylinder
5 fuel injector
Cylinder
6 fuel injector
Oil level sensor
-
Signal. VANOS inlet valve
Signal. VANOS outlet valve VANOS
inlet valve
VANOS outlet valve

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Fuel Injection
Table c. Siemens MS 42.0 and MS 43.0 ECM pin assignments (continued)
Pin
42
43
44
45
46
47
48
49 50
51
52 Componentlfunction
Signal, evaporative emissions valve
Signal, throttle
valve drive
Signal, throttle valve drive
Signal, engine coolant thermostat
Signal, close idle speed control valve
Signal, open idle speed control valve
Signal, shield
ltnock sensor
Signal, resonance valve
intake system
Not used
Not used
Signal, secondary air injection pump valve
Signal
Input
Input
Input
Input
input
Input
Ground
Input
Input
Notes
Evaporative emissions valve
Throttle valve
Throttle valve Engine coolant thermostat (map controlled)
idle speed control valve
Idle speed control valve
Shield,
knock sensor
Resonance valve intake system
Secondary air injection valve
Connector
X60004 40-pin Notes
instrument cluster control unit
Instrument cluster control module
Secondary air injection pump relay
Electric (auxiliary) fan motor
Pedal position sensor (PWG) (MS 43.0)
Pedal position sensor (PWG) (MS 43.0)
Pedal position sensor (PWG) (MS 43.0)
Fuel pump relay
1
Instrument cluster control module
ComponenVfunction
Signal, battery charge indicator lamp
Feedback signal, engine start
Signal, secondary air injection pump
Signal, electric cooling fan
Not used
Not used
Pedal position sensor (PWG) (MS 43.0)
Signal, pedal position sensor (PWG) (MS 43.0)
Pedal position sensor (PWG) (MS 43.0)
Signal,
fuel pump relay 1
Signal, oil pressure switch
Pin
1
2 3
4
5
6
7
8
9
10
11 Signal
Input
Input
input
input
Input
Input