1999 BMW 528i Idle

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Fuel Injection
SIEMENS MIS 42.0 AND 43.0
When system faults are detected, a diagnostic trouble code
(DTC) is stored in the engine control module (ECM). The MIL
also illuminates
if an emissions-related fault is detected.
When faults arise, or
if the malfunction indicator lamp (MIL) is
illuminated, begin troubleshooting by connecting BMW ser-
vice tester
DISplus, MoDiC, GTI or equivalent scan tool. The
capabilities of OBD
II software has the potential to save hours
of diagnostic time and to help avoid incorrect component re-
placement and possible damage to system components.
CAUTION-
* The tests in this section may set fault codes (DTCs) in tlie
ECM and illuminate the MIL. After all testing is completed,
access and clear DTC fault
memory using an OBD I/ or
BMW compatible scan tool. See
OBD On-Board Diag-
nostics.
Only use a
dgital multimeter for electrical tests.
Relay positions can vary. Be sure to confirm
relayposi-
tion by identifying the wiring in the socket using the wir-
ing diagrams found in
ELE Electrical Wiring
Diagrams.
NOTE-
- OBD I1 fault memory. (including an illuminated MIL! can
only be reset using the special scan tool. Removing the
connector from the ECM or disconnecting the battery will
not erase the fault memory.
The BMW-dedicated 20-pin diagnostic
linlc connector
(DLC) is in the right rear of the engine compartment The
20-pin DLC is discontinued on models after
6/2000.
The 1 &pin OBD I1 diagnostic connector (arrow) is located
inside the car on the lower left dash panel.
The MS
42.0 and MS 43.0 systems manage the following
functions.
- Air:
Idle speed valve
Electronic throttle
Hot film mass air flow (MAF) sensor
Resonance-turbulence intake control
- Fuel:
* Fuel supply
Running losseslnon return
Fuel injection

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Fuel Injection
ECM relay, testing
The engine control module (ECM) relay is energized via the
ECM and supplies battery positive
(Bc) power to many of the
engine management components and subsystems. If this re-
lay is faulty, the engine will not start.
NOTE-
The ECM relay is also referred to as the DME main relay
ECM relay powers:
ECM
Ignition coils
* Fuel injection
Evaporative leak detection pump
Idle air actuator
- Camshaft sensors Evaporative emissions valve
Hot film mass air flow sensor
Fuel pump relay
Oxygen sensor heaters
4 Working in right rear of engine compartment:
Release interior ventilation filter cover latch
(A) and re-
move cover.
Release plastic locking tab
(B).
Rotate duct inward (arrow) to unlock 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.
With ignition off, remove ECM relay (arrow) in electronics
box (E-box) at rear of engine compartment, right side.
NOTE-
Relay locations can vary Confirm relay identification by
matching wiring colors and terminal numbers.

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Fuel Injection
A faulty MAF sensor can produce the following problems:
Difficult to restart when engine is hot
Engine starts then stalls
* Engine starts and runs only with accelerator pedal de-
pressed
4 Disconnect electrical harness connector from MAF sensor
(B).
- Turn ignition on and checlc for voltage and ground at connec-
tor.
There should be ground at pin
1 and battery voltage at pin
3.
- If any faults are found, checlc for wiring breaks between
MAF sensor and ECM and between MAF sensor and main
DME relay.
NOTE-
Visually inspect the sensor for damage, missing or blocked
screens. The screens affect air flow calibration. Also inspect
the sealina
0-rinas where the sensor inserts into the air filter - - housing and intake boot. Ensure the pin connections are
clean and tight.
4 Connect a BMW-compatible scan tool or an OED II generic
scan tool.
Checlc air mass signal (load signal) with the engine
at idle. Raise idle speed and
checlc that load signal changes
with rpm.
CAUTION-
Be sure ignition is OFFbefore disconnecting or reconnecting
DME system components.
Remove MAF sensor:
Loosen intake boot clamp
(A).
Disconnect harness connector (6).
* Release clip from air filter housing (C) and remove sensor.
- Installation is reverse of removal.
No adjustment to MAF sensor is possible.
Check intake hoses for cracks and vacuum
lealts.

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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.
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130-36
[~uel Injection
4 Remove nuts and bolts (arrows) retaining wiring harness to
throttle housing.
- Working at throttle housing, turn harness plug countercloclc
wise and remove.
4 Working at side of intake manifold, disconnect electrical bar-
ness connectors:
Idle control valve (A)
Intake manifold resonance valve (B)
- Disconnect electrical harness connectors at oil pressure
sender and oil temperature sender at base of oil filter hous-
ing.
4 Remove dipstick guide tube:
Disconnect wiring harness brackets from tube
(A)
Unclip fuel lines from tube (B).
Remove lower guide tube mounting bolt (C).
Pull out dipstick guide tube.

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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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. .
Fuel Injection
Check resistance of valve across valve terminals
Idle speed control valve coil resistance
Terminals
1 and 2 20 i2.0.
Terminals 2 and 3 20 i2.0.
Terminals 1 and 3 40 i4.0.
CAUTIOIG
Be sure ignition is OFFbefore disconnecting or reconnecting
DME system components.
- To remove valve, remove cable bracket mounting bolt and
idle speed control valve mounting bracket bolts from front of
throttle housing and remove idle speed control valve with at-
tached bracket.
NOTE-
When installing idle speed control valve, remove intake boot
sealing ring from valve and install into intake air boot. Then
install valve info sealing
ring.
Evaporative emissions control diagrams
MS 42.0 (LDP) ,-a"-
Evaporative emissions control,
(MS 42.0, MS 43.0)
E39 models with MS 42.0 or MS 43.0 engine are equipped
with a fuel system evaporative pressure leak diagnosis sys-
tem. The main component of this system is the leak diagnosis
pump (LDP or DM-TL). The function of either system is to
pressurize the fuel tank and the evaporative emission system
for the purpose of detecting leaks.

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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