Fault Conditions

P1908
No Bus Data From MIU.

NOTE: Refer to Information Bus, Fault Diagnosis, Fault symptoms for Bus and Diagnostic Communication errors. Testing and Inspection

Fault symptoms
Some of the following symptoms may be observed:
- Engine will not start.
- Cruise control not working.
- AC 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).

On-Board Diagnostics
Type of diagnosis:
- Continuous. But interrupted when fault criteria fulfilled and does not restart until next driving cycle.

Enable conditions:
- Engine running.

Fault criteria:
- No communication for more than 3 S.

Dependents:
- None.

System reaction to a fault:
- Cruise control blocked.

OK report:
Fault handling: See "Fault diagnosis, general" for more information.
- Enable criteria fulfilled and fault criteria not fulfilled within 60 s.
- Type III. CHECK ENGINE does not go on.

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 multi meter, diagnostic tool or test lamp during the check.

Proceed to Diagnostic Procedures Reference