What this code means

The PCM is not receiving communication messages from the Transmission Control Module over the CCD or J1850 data bus. This loss of communication prevents the PCM and TCM from coordinating engine and transmission operation.

Symptoms

• Check Engine Light
• Transmission stuck in limp mode (2nd gear)
• Harsh or no shifting
• Speedometer may not work
• Cruise control inoperative

Common causes

• Faulty TCM
• Data bus wiring open or shorted
• Corroded data bus connector
• TCM power or ground loss
• Faulty PCM data bus driver

Diagnostic steps

1. Check for TCM power and ground
2. Inspect data bus wiring between PCM and TCM
3. Test data bus communication with scan tool
4. Check data bus termination resistance
5. Scan TCM for stored codes if communication can be established

Repair notes

Repair data bus wiring between the PCM and TCM; replace the TCM if it has lost power or failed internally.

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