Check Engine Code
U0101
Lost Communication With TCM
Severity: high
DIY difficulty: 3/5
Typical cost: $80–$1500
What U0101 means
The TCM has gone silent on the CAN bus. Often pairs with transmission limp mode.
Symptoms
- CEL
- Transmission stuck in one gear
- Erratic shifts or no shifts
- Speedometer issues
Likely causes (most common first)
- Failed TCM
- Damaged wiring to the TCM
- CAN bus fault
- Power/ground issue at the TCM
Can I keep driving?
High — risk of damage if ignored
Typical repair cost
DIY fixes can start near $80 (parts only). Shop repairs for U0101 typically run up to $1500 depending on the underlying cause and vehicle. Start with the most common cause — Failed TCM — before throwing parts at it.
Related codes
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