1997 BMW 528i Car engin

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130-28
Fuel Injection
ECM Relay
4 Check for voltage at terminal 6 (30) at reiay socket
If battery voltage is present continue testing.
if battery voltage is not present, check fuse 109 (80-amp
fusible link) under passenger seat carpet. See 610 Electri-
cal
Component Locations.
- Reinstall relay and turn ignition on. Gain access to back side
of reiay socket and check for ground at terminal
4.
If ground is present continue testing.
If ground is not present, signal
from ECM is missing. Check
wire between ECM and relay.
- With ignition on and reiay installed, check lor battery voltage
at terminal
2.
If battery voltage is present, relay has energized and is
functioning correctly.
If battery voltage is not present and
ail earlier tests are OK,
relay is faulty and should be replaced.
NOTE-
If no faults are found during testing but power is not reaching
the ECM or other components, check the fuses
in the fuse
carrier
X8680 in the E-box.
Mass air flow (MAF) sensor, checking and
replacing
4 The hot f~lm mass air flow (MAF) sensor sends a varying volt-
age (approx. 0.5 - 4.5 vdc) to the ECM representing the mea-
sured
Intake air. The alr mass input signal is produced
electron~caily uslng an electrically heated metal fllm in the air
flow stream.
The ECM relay provides the operating voltage to the MAF
sensor. As air
flows through the sensor, the film is cooled. To
maintain the film at a constant temperature, additional current
is necessary. It is this additional current that is the basis lor
the input signal.
If there is no output signal from the MAF sensor, the ECM op-
erates the engine using the throttle position and engine rpm
inputs. A faulty MAF sensor illuminates the MIL.

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/Fuel Injection
4 Remove dipstick guide tube:
Disconnect wiring harness brackets from tube (A).
Unclip fuel lines from dipstick tube
(El).
Remove lower guide tube mounting bolt (C). Pull out dip-
stick guide tube.
< If necessary, disconnect electrical harness connector at fuel
tank venting valve (A). Disconnect hose at quick disconnect
fitting (arrow).
Working at throttle housing, turn harness plug counterclock-
wise and disconnect. Remove throttle assembly mounting
fasteners (arrows) and pull assembly off manifold.
Installation is reverse of removal
Replace sealing ring between throttle assembly and intake
manifold.
0 Reattach throttle assembly harness connector with care.
Arrow on fully tightened connector must line up with corre-
sponding arrow on throttle assembly housing.
* Connect BMW test equipment or equivalent and carry out
throttle plate adaptation following the on-screen directions.
Reattach throttle cable and check cable adjustment as de-
scribed under Throttle cable, adjusting
(MS 42.0).

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-.
Fuel Injection 1
4 If necessary, disconnect electrical harness connector at fuel
tank venting valve (A). Disconnect hose at quick disconnect
fitting
(arrow).
< Worlting at throttle housing, turn harness plug counterclock-
wise and disconnect. Remove throttle assembly mounting
fasteners
(arrows) and pull assembly off manifold.
- Installation is reverse of removal.
0 Replace sealing ring between throttle assembly and intake
manifold.
Reattach throttle assembly harness connector with care.
0 Arrow on fully tightened connector must line up with corre-
sponding arrow on throttle assembly housing.
- Use BMW scan tool to reset ECM adaptation values.

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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
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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130-46
Fuel Injection
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
OED 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.
CA UTIOiU-
The tests in this section may set fault codes (DTCs) in the
ECM and illuminate the MIL. After ail testing is completed,
access and clear DTC fault
memory using an OED I/ or
BMW compatible scan tool. See OBD On-Board Diag-
nostics.
Only use a digital
multimeter for electrical tests.
Relay positions can vary. Be sure to confirm relay
posi-
. tion by identifying the wiring in the socket using the wir-
ing diagrams-found in ~~~~lectrical Wiring
Diagrams.
NOTE-
OED 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 link connector
(DLC) is in the right rear of the engine compartment.
The 16-pin OBD
I1 diagnostic connector (arrow) is located
inside the car on
the lower left dash panel.

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130-50
Fuel Injection
Bosch M5.2
ECM relay
1 HoL al ail iirnel XOL a1 ail limes
i--[-----i F109 (BOA) electronics I L.$.....: .I:
ECM relay . . . . . . . . . ,
8,s
:,
6 1 .. ... ~~.~~. . ...... .-, Engine control ii~~-~.~~..~ ........ ~~~~~~.~~~~:. module relay -;I
Of?
,c,;,,,
< With ignition off, remove ECM relay (arrow) in electronics
box (E-box) at right rear of engine compartment.
NOTE-
Relay locations can vary. Conh relay identification by
matcliing wiring colors and terminal numbers.
4 Check for voltage at terminal 6 of main relay socket (30-red
wire). On M5.2 cars also check for battery voltage at terminal
8.
. . . . . . . . . ,
If battery voltage is present, continue testing
.
If battery voltage is not present, check large red wire(s) in
relay socltet. See
ELE Electrical Wiring Diagrams.
%P,,tt
- Reinstall relay and turn ignition on. Gain access to underside
of relay socket and
checlc for ground at terminal 4 (85-brown
wire).
. . . . . . . . . . . . - - - - - - - - - . - - - . . l ,,-. ; Engine i f .: , ; Fuse carrier .,A . :engine /;is? /control L.!.!! .... 1.: ...... !.::..! I lij :module electronics If
ground is present, continue testing
If ground is not present, signal from ECM is missing. Checic
wire between ECM and relay.
4 With ignition on and relay installed, check for battery voltage
at terminal
2 (87-redlwhite wire). On M5.2.1 cars also checlc
for battery voltage at terminal 5.
If battery voltage is present, relay has energized and is
functioning correctly.
If battery voltage is not present and all earlier tests are OK,
relay is faulty and should be replaced.

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130-54
I Fuel Injection ldle speed control valve,
testing and replacing
ldle speed is maintained by the ECM through the idle speed
control valve. The idle control function compensates for en-
gine load and engine operating conditions. ldle speed is
adaptive through the ECM and no adjustments can be made.
Before checking valve, confirm that throttle position sensor is
working correctly.
NOTE-
The test given below is an electrical check only. It does not
check the mechanical operation of the valve. If the valve is
sticking, hanging up or is sluggish in operation, substituting a
Inown good valve is the best way to check it.
With engine running, check that idle speed control valve is
buzzing.
Turn on
AIC or shift car into drive. ldle should remain steady
or increase slightly.
If valve is not buzzing, or if idle decreases in step above, stop
engine and disconnect harness connector from valve.
4 Check resistance of valve across its terminals. Test values
are listed below.
ldle speed control valve coil resistance
Terminals
1 and 2 20 +2%
Terminals 2 and 3 20 +2Q
Terminals 1 and 3 40 +4%
NOTE-
If you suspect an intermittent fault, lightly tap the valve while
testing resistance.
With valve harness connector disconnected, check for bat-
tery voltage at redlwhite wire in connector with ignition on.
If . ~~ ~~
there is no voltage, check wiring between connector and 7 ECM relay. See ELE Electrical Wiring Diagrams.
NOTE- - The idle speed control valve receivespositive (+) battery volt-
age from the ECM (DME main) relay