U0101
NetworkModule Communicationhigh severityLost Communication with TCM
What U0101 Means
Cannot communicate with the Transmission Control Module.
Symptoms
- Check Engine Light
- Transmission in limp mode
- Harsh shifting or no shifting
- Trans warning light
Common Causes
- TCM power/ground failure
- CAN bus wiring to TCM
- TCM failure
- Fuse blown
Diagnostic Steps
- Check TCM fuses
- Test power and ground at TCM
- Check CAN bus wiring
- Try direct communication with TCM
Where to start: Check fuses and power supply. Verify CAN bus.
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