Trouble codes › P0118
P0118 Engine Coolant Temperature Circuit High
Cooling
P0118 means the coolant temperature sensor reads extremely cold because its circuit is open, often an unplugged sensor.
The coolant temperature sensor's signal voltage is too high, which the engine computer reads as an extremely cold engine. It's usually an unplugged sensor, an open wire or a failed sensor.
Usually drivable, but the gauge may read cold even if the engine is hot, and the engine may run rich. Get it fixed soon and watch for steam or overheating.
Common causes
- An unplugged or corroded sensor connector
- An open wire in the sensor circuit
- A failed coolant temperature sensor
Symptoms
- Temperature gauge stuck cold
- Black smoke or poor fuel economy
- Fans running constantly on some vehicles
What to check first
- Check that the sensor is plugged in (common after cooling system work).
- With a scan tool, a reading around -40°F means an open circuit.
- Briefly jumper the connector's two terminals (as your service information describes): the reading should jump to very hot. If it does, replace the sensor.
- Repair any open wiring.
What does P0118 mean on your vehicle?
The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.
Ask iRepair about P0118No scanner? Most auto parts stores read check-engine codes for free.
Related codes
General guidance for P0118 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.