P0687
ECM/PCM Power Relay Control Circuit High
P0687 is an OBD-II diagnostic trouble code meaning: ECM/PCM Power Relay Control Circuit High. Common causes: short circuit of the control wire to the +12 v power line, open ground circuit of the relay control coil. Estimated repair cost: $6–111.
Symptoms
- Unstable engine operation
- Check Engine Light
- Slow battery discharge (relay remains on)
- Malfunctions of electronic systems
- Possible spontaneous engine start
Causes
- Short circuit of the control wire to the +12 V power line
- Open ground circuit of the relay control coil
- ECU power relay malfunction
- Damage to wiring or connectors
- Internal ECU fault
How to Fix
- Read OBD-II codes and record all errors
- Locate the ECU power relay according to the electrical diagram
- Measure the control signal voltage at the relay
- Check the control wire for short to +12 V
- Check the control coil ground circuit for an open circuit.
- Check relay; if the external circuit is working properly - ECU diagnostics
Related codes
Error P0687 by Vehicle Brand
FAQ
What does the P0687 code mean?
P0687 is an OBD-II diagnostic trouble code that indicates: ECM/PCM Power Relay Control Circuit High
What causes a P0687 error code?
The most common causes of P0687 include: Short circuit of the control wire to the +12 V power line; Open ground circuit of the relay control coil; ECU power relay malfunction; Damage to wiring or connectors.
How do I fix a P0687 diagnostic trouble code?
To fix P0687: Read OBD-II codes and record all errors. Locate the ECU power relay according to the electrical diagram. Measure the control signal voltage at the relay. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P0687?
Do not drive — repair immediately
How much does it cost to fix P0687?
The estimated repair cost for P0687 is $6–111. Actual cost depends on your vehicle, location, and labor rates.
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