U1803

U1803 00

TCM was Missing on Bus







Fault symptom
- Messages shown in SID.

On-board diagnosis

Type of diagnosis:
- Continuous

Enable criteria:
- Engine running and not in limp home mode.
- Voltage is over 9V but under 16V.

Fault criteria:
- No bus communication.

System reaction to a fault:
- Limp home

Checking the wiring harness
- Move the wiring harness at several spots and in several directions to reveal intermittent breaks and short-circuits. Check switches, connectors and crimp connections for oxidation, retracted pins and pin clamping force.

Diagnostic help
- In order to read DTC from Trionic TCM, communication with CIM is required. If the DTC is stored and read with the diagnostic instrument, it indicates intermittent bus-lead fault.