P1622

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 P1623). CHECK ENGINE.

P1622

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 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:

-	Enable criteria fulfilled and fault criteria not fulfilled within 60 s.

Fault handling: (For more information, see Fault handling III, other emission-related components and functions

-

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.

Diagnostic procedure

For more detailed fault diagnosis, see ”Bus and diagnostic communication" P1622 .