P0118: Engine Coolant Temperature Sensor 1 Circuit High
What to do
Expect poor economy and possibly a rough-running engine that never seems to warm up properly. Worth fixing promptly, as prolonged over-fuelling washes oil from the bores and loads the catalytic converter.
What this code means
The coolant temperature signal is above its valid range, usually an open circuit, which the module reads as extremely cold. It responds with heavy cold-start enrichment that never stops, producing a rich-running engine, poor economy and eventually fouled plugs. A disconnected sensor gives exactly this reading.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Corroded or loose connector · easy
- Faulty engine coolant temperature sensor · easy
Less common
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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