U0100: Lost Communication With ECM/PCM A
LowNetwork/CommunicationCommunication Bus
What does U0100 mean?
U0100 is a diagnostic trouble code indicating "Lost Communication With ECM/PCM A". The vehicle's main computer has lost its ability to communicate with a specific module over the data bus. This could be caused by a wiring fault, a blown fuse, or a failed control module.
Common causes
- Failed control module
- CAN bus wiring fault or short
- Blown fuse to the affected module
- Water intrusion in a connector or module
- Battery voltage too low
What should you do?
This is a minor or informational code. Monitor for any changes in vehicle behaviour and address it during your next scheduled service visit.
Get a diagnosis for YOUR car
Code U0100 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.