P0690: Engine Control Module Power Relay Sense Circuit High
What to do
Driveable, but likely to flatten the battery if the car stands for several days. If the vehicle has also been forgetting its settings or storing memory faults, that is consistent with a relay that never releases.
What this code means
The power relay sense circuit reads high when the module expects it low — voltage is present when the relay should be open. The usual meaning is a relay whose contacts have welded closed, leaving the module powered after the ignition is switched off.
That matters for two reasons: the battery drains over days, and the module never completes its normal shutdown, which is one of the ways learned settings become corrupted.
Likely causes
Start here
- Failed ECM power relay · easy
- Corroded relay socket · easy
Less common
- Signal wire shorted to voltage · moderate
- Failed control module · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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