Powertrain Control Module Power Relay Control Circuit Open
Table of contents
P0685 MERCURY Possible Causes
- Faulty Powertrain Control Module (PCM) Power Relay
- PCM Power Relay harness is open or shorted
- PCM Power Relay circuit poor electrical connection
- Blown PCM fuse
- Faulty PCM
How do I fix code P0685 MERCURY?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- Check all the Engine Control Module (ECM) fuses, if the fuses are OK, then replacing the ECM relay should take care of the problem.
Cost of diagnosing the P0685 MERCURY code
The cost of diagnosing the P0685 MERCURY code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0685 MERCURY Description
This DTC sets when the ignition switch position run circuit indicates the ignition is in the OFF, ACC, or LOCK position, and the amount of time the Powertrain Control Module (PCM) remains powered through the PCM power relay exceeds a predetermined amount of time.