ECM or PCM Power Relay Sense Circuit Low
The voltage sense line that confirms the main ECU power relay has actually closed reads low - either the relay is not closing or the sense line is shorted to ground.
Affected components
- Ecm power relay
Common causes
- High likelihood: Relay does not close
- Low likelihood: Connector pins corroded - high contact resistance
- Low likelihood: Harness chafing through insulation
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
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.