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.
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.
Common causes
- high
Relay does not close
One of the most commonly reported causes for this code — check this first.
Typical part cost: $90-390
- low
Connector pins corroded - high contact resistance
Less common, but worth ruling out after the more likely causes.
Typical part cost: $90-390
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does P0689 mean?
P0689 means "ECM or PCM Power Relay Sense Circuit Low". It is a generic OBD-II code that points to a fault in the computer & auxiliary output controls.
What are the most common causes of P0689?
relay does not close; connector pins corroded - high contact resistance; harness chafing through insulation — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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