ECM/PCM Power Relay Control Circuit High

Where it lives

For P0687, the relay sits on the circuit this code reports. The description of P0687 reports a fault at the relay.

Check these first

• A short to voltage in the relay control circuit
• A stuck power relay
• Corroded relay wiring
• Overvoltage from the charging system
• Aftermarket wiring tied into the circuit

What to do next

1. Monitor the relay control voltage live
2. Trace the circuit for a short to power
3. Test the relay for sticking
4. Check charging voltage
5. Remove stray add on wiring and replace the relay
6. Clear the code and retest

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