U0100High severity
Lost Communication With ECM/PCM 'A'
A control module has lost communication with the Engine/Powertrain Control Module over the CAN bus.
Common causes
- Faulty CAN bus wiring
- Failed ECM/PCM
- Poor ground or power supply
- Corroded connectors
Possible symptoms
- Multiple warning lights
- No-start condition
- Erratic gauge behaviour
Code breakdown
U — System
Network & Vehicle Integration (communication buses)
0 — Type
Generic (SAE standard, common to all manufacturers)
1 — Subsystem
Fuel and air metering