OBD-II code guide
P0118 Engine Coolant Temperature Sensor Circuit High
P0118 means the coolant temperature sensor circuit is reading out of range, often as extremely cold.
What it means
The engine computer cannot trust coolant temperature data for fuel, fan, and warm-up decisions.
Common symptoms
- Check engine light
- Hard starting
- Cooling fans running constantly
- Poor fuel economy
- Temperature gauge abnormal
Likely causes
- Faulty coolant temperature sensor
- Unplugged connector
- Damaged wiring
- Low coolant around sensor
- Corroded connector
First checks
- Check coolant level when cold.
- Inspect the sensor connector.
- Compare scanner coolant temperature to actual cold engine temperature.
- Do not open the cooling system hot.