P1908
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Some of the following symptoms may be observed:
Engine will not start.
Cruise control not working.
A/C malfunctioning.
Radiator fan runs continuously.
Main instrument unit gauges and indicators not working.
Additional trouble codes in Trionic (P1901).
Additional trouble codes in TCM (P1902 or P1923).
CHECK ENGINE.
No Bus Data From MIU. See Fault Tracing 3:5 Bus and Diagnostic Communication.
Fault symptoms
Some of the following symptoms may be observed:
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Cruise control not working.
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Radiator fan runs continuously.
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Main instrument unit gauges and indicators not working.
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Additional trouble codes in Trionic (P1901).
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Additional trouble codes in TCM (P1902 or P1923).
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On-Board Diagnostics
Type of diagnosis:
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Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.
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Enable criteria:
Fault criteria:
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No communication for more than 3 s.
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Dependents:
System reaction to a fault:
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Cruise control blocked.
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OK report:
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Enable criteria fulfilled and fault criteria not fulfilled within 60 s.
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Fault handling:
(See section
Fault handling III, other emission-related components and functions
for more information.)
Diagnostic help
Fault diagnosis concerns an intermittent electrical fault in the power supply to the transmitting control module or any of the bus leads.
Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.
