P0690 ECM/PCM Power Relay Sense Circuit High

P0690 indicates a high condition in the ECM or PCM power relay sense circuit. The module sees relay output or sense voltage above the expected range.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Computer
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not leave a backfed PCM power circuit unresolved because it can cause battery drain and unpredictable module behavior.

Useful checks before replacing parts

Check relay sense voltage, relay command, ignition state, charging voltage, PCM power feeds, freeze-frame data, and symptoms of modules staying powered.
Inspect for short-to-voltage faults, stuck relay contacts, backfeed through aftermarket equipment, open grounds, crossed wiring, and fuse block corrosion.
Confirm whether the sense circuit remains high with the relay removed or ignition off to separate relay and harness faults.

Related OBD-II codes

These nearby computer entries can help compare wording and fault area. They may share the same verification status as the source database.