ECM/PCM Power Relay Control Circuit Open
The control circuit for the ECM main power relay is open. Without this relay, the controller cannot maintain its keep-alive supply.
Affected components
- Ecm
- Main relay
- Relay wiring
Common causes
- High likelihood: Main relay defective
- Medium likelihood: Relay control wire open
- Low likelihood: Pin pushed back out of connector body
Possible symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.