ECM/PCM Power Relay Sense Circuit Intermittent
The sense (feedback) line that lets the ECM verify the main power relay has actually closed shows intermittent dropouts. The ECM expects to see battery voltage on this line whenever the relay is energised — short losses suggest aged contacts, vibration or chafed wiring.
Affected components
- Main relay
- Sense wire
Common causes
- High likelihood: Aged main relay contacts
- Medium likelihood: Chafed sense wire shorting intermittently
- Low likelihood: Connector with intermittent contact under vibration
Diagnostic notes
- The malfunction indicator lamp may illuminate
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.