What causes a P0685 code?

Common causes: Failed relay; Wiring.

What are the symptoms of a P0685 code?

Typical symptoms: Intermittent stalls; No start.

No — this code can cause damage if you keep driving. Get it diagnosed before continuing. Estimated repair: $30-$300.

OBD-II Code · Computer

ECM/PCM Power Relay Control Open

high severityDo not drive$30-$300

PCM main power relay circuit open.

Common symptoms

Likely causes

Where to start

Try the cheapest cause first. Start by checking: failed relay.
Cost & scope. $30-$300
If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there. Don't keep driving with this one active — risk of damage.

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