P1622

P1622

No Bus Data From MIU. See Fault Tracing 3:5 Bus and Diagnostic Communication.







Fault symptoms
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 diagnostic trouble codes in TCM (P1902 or P1623).
- CHECK ENGINE.

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

Enable criteria:
- 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.) Initial Inspection and Diagnostic Overview
- Enable criteria fulfilled and fault criteria not fulfilled within 60 s.
- Type III.

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.