Error code
OBD2 P0688
OBD2P0688
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
ECM/PCM Power Relay Sense Circuit /Open.
Severity
moderateCan drive but may experience issues with starting or running.
Summary
P0688 indicates an issue with the engine control relay, specifically a short to positive in the power relay sense circuit.
Common Causes
- Wiring short to positive on the engine control relay
Fixes
- Replace the faulty engine control relay.
FAQ
What is causing P0688?
A short to positive in the wiring of the engine control relay.
How do I fix it?
Replace the faulty engine control relay. Specific part numbers and costs may vary by vehicle make and model.
Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
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