TCM Communication Circuit
The Transmission Control Module communication circuit reports a communication circuit fault. Data exchange between TCM and ECM is impaired.
Affected components
- Tcm
- Wiring harness
- Ecm
Common causes
- High likelihood: Communication bus fault
- Medium likelihood: TCM internal fault
- Low likelihood: Gateway module routing CAN messages incorrectly
Possible symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Diagnostic notes
- The malfunction indicator lamp may illuminate
- Reduced-power or limp mode may occur
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.