Powertrain
generic / SAE
P0689
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.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number6 / 89
Possible causes
- Relay does not close high
- Connector pins corroded - high contact resistance low
- Harness chafing through insulation low
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–350 €
- Estimated time: 0.5–1.8 h
- Component: ecm power relay
- MIL / check engine light
Sources
References
sae:J2012