Bus and Diagnostic Communication

P1623
No Bus Data From TCM.






Fault Symptoms
No bus communication with TCM

Condition
The following conditions are applicable:
Trionic:
^ Engine has started
^ The TCM has been present on the bus at some time previously
^ No communication for 3 seconds.

Diagnostic Help
Some of the following symptoms may be observed:
^ Diagnostic trouble code P1921 or P1902 in TCM (if TCM can be contacted)
^ Additional diagnostic trouble codes in Trionic (P1901, P1902 or P1622).
^ Engine fails to start.
^ Automatic transmission in Limp-Home mode (CHECK GEARBOX lamp on)






Checking The Wiring Harness
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short-circuits in the leads. Observe the multimeter, test lamp or diagnostic tool during the test.