AutoCodes

OBD-II / U0100

Lost communication with engine control module

One or more modules stopped receiving expected messages from the engine or powertrain controller.

Possible causes

  1. 01Weak battery or voltage drop
  2. 02Poor connector or ground
  3. 03CAN network wiring
  4. 04Module temporarily offline

Safe checks

  • Check battery voltage first.
  • Save every U-code present.
  • Do not bridge network wiring without the technical diagram.

정비소 진단을 대신하지 않습니다. 먼저 이해하고 판단하도록 돕습니다. Original editorial content; always confirm manufacturer procedures and specifications.