P0690
ECM/PCM Power Relay Sense Circuit High
Power supply / ECM relay
Generic OBD-II
High
What it means
P0690 means the engine computer sees a higher-than-expected voltage on the circuit that monitors its main power relay. This usually points to a relay that is stuck closed or a sense wire shorted to voltage. It is often drivable, but a relay that will not switch off can drain the battery and cause intermittent electrical problems, so it should be diagnosed.
High
Can I keep driving? Often drivable, but a stuck relay can drain the battery or cause intermittent electrical faults and occasional stalling — have it diagnosed soon.
Common symptoms
What you'll notice
- Check-engine light on, sometimes with other electrical warning lights
- Battery draining or the system staying powered after shutdown
- Intermittent stalling or hard restart
- Other electrical or sensor codes appearing alongside it
Common causes
Most likely first
- ECM/PCM power relay sticking closed or failingLikely
- Short to voltage in the relay sense wiringCommon
- Corroded or loose connectors in the sense circuitCommon
- Poor ground or, less often, an internal ECM/PCM faultLess often
How to diagnose & fix
Work through it in order
- Scan for all stored codes and note anything set at the same time.
- Check the power relay operation — confirm it de-energizes when the key is off.
- Test the sense circuit for a short to voltage and inspect its connectors.
- Replace the relay if it sticks; treat ECM/PCM replacement as a last resort after wiring is ruled out. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0690?+
Usually short term, but a relay that will not switch off can drain the battery or cause intermittent stalling, so get it checked.
Can I just clear P0690?+
It will return unless the relay or its sense wiring is repaired.
Related codes
Often seen with P0690
Read & clear P0690 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX