U0100
Lost Communication With ECM/PCM
Network & Communication · Network & Communication
high
What does this code mean?
The vehicle lost communication with the engine/module control module over the network bus.
This is a generic OBD-II / UDS code — the meaning is standardized across manufacturers.
Possible symptoms
Check EV system
Vehicle does not start
Reduced power
Possible causes
- 1.Module fault
- 2.CAN bus wiring issue
- 3.Faulty ground or power to a module
- 4.Software fault
These are possible causes — a professional inspection is required to confirm.
Diagnostic procedure & recommended checks
- Check network bus wiring and terminators
- Check module power/ground
- Read all network DTCs
Recommended actions
- Professional network diagnostics
Can I drive?
Yes, with warnings — inspect soon
When to contact a professional
If intermittent or affecting driveability.
Related Fix & Solve guides
Diagnostic information is provided for informational purposes and does not replace professional inspection. High-voltage systems must only be serviced by qualified personnel.