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.

整備工場の診断に代わるものではありません。理解して判断するための手助けです。 Original editorial content; always confirm manufacturer procedures and specifications.