U0100 is rated as critical severity. Stop driving — risk of damage or safety hazard.

U0100

Lost Communication With ECM/PCM "A"

Q: What does code U0100 mean?

Lost Communication With ECM/PCM "A": The vehicle has lost communication with the engine control module. Can cause no-start conditions.

Network Code · Critical

What does U0100 mean?

The vehicle has lost communication with the engine control module. Can cause no-start conditions.

System: Module Communication

U0100 is a network diagnostic trouble code indicating lost communication with ecm/pcm "a". This code is classified as critical severity, which means: stop driving — risk of damage or safety hazard.

Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your vehicle.