P1921
Read the instructions below then
start the fault diagnostic procedure.
Symptom: No bus communication with Trionic
No Bus data From TRIONIC.
Fault symptoms
No bus communication with Trionic
Condition
The following conditions are applicable:
TCM:
|
•
|
The automatic transmission's input shaft speed exceeded 200 rpm once during the present drive cycle
|
|
•
|
No communication for 4 seconds.
|
Diagnostic help
Some of the following symptoms can
perhaps
be observed:
|
-
|
Diagnostic trouble codes P1923, P1908, P1901 or P1902 in Trionic (if the Trionic can be contacted)
|
|
-
|
Additional diagnostic trouble code in the TCM (P1902).
|
|
-
|
Automatic transmission in Limp-Home mode (CHECK ENGINE 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.
