OBD-II code · Network

U0402 Invalid Data Received from TCM

A control module is communicating with the transmission control module but receives implausible data — wrong checksum, frozen value, or out-of-range value. Often results in transmission limp-home.

Is it safe to drive with U0402?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • PossibleTCM software bug or outdated calibration
  • PossibleTCM internal sensor or processing fault
  • PossibleCAN corruption causing checksum errors

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
1–5 h
Emissions test
Usually unaffected
Parts involved
Tcm, Can Bus Wiring

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.