U0101 Lost Communication With TCM

Network Severity: Moderate Generic OBD-II

A module cannot communicate with the transmission control module.

Common causes

  • Transmission module without power
  • Network wiring problem
  • Faulty module

Symptoms

  • Limp mode
  • Gear indicator missing

What to check

  1. Check TCM power and ground
  2. Check network wiring

Manufacturers may add their own detail to generic codes. If your vehicle shows a different description for U0101, follow the service information for that make and model.

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