BMW 5251 Service Manual page 413

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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 I I 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-
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OBD I 1 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 I 1 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.
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Air:
Idle speed valve
Electronic throttle
Hot film mass air flow (MAF) sensor
Resonance-turbulence intake control
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Fuel:
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Fuel supply
Running losseslnon return
Fuel injection