P0687: Engine Control Module Power Relay Control Circuit High
What to do
May not start. Test the relay and its socket before anything expensive — this is one of the cheaper causes of a complete no-start.
What this code means
The engine module power relay control circuit is reading high — an open, or a relay coil that has failed open. The relay does not energise, so the module and everything it supplies stay unpowered and the engine cranks without starting.
Likely causes
Start here
- Failed ECM power relay · easy
- Broken wire in control circuit · moderate
- Corroded relay socket · easy
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
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