P0116 — Engine Coolant Temperature Circuit Range/Performance Problem

What it means

The coolant temperature signal is electrically valid but implausible: the engine warms up too slowly, the reading does not rise as expected after start, or it differs too much from the intake air temperature. The control module then keeps warm-up enrichment active for too long, which raises fuel consumption and can cause rough running and poor heater output.

Likely causes (most common first)

1. Thermostat stuck open, so the engine never reaches operating temperature
2. Coolant temperature sensor drifted out of calibration or reacting slowly
3. Low coolant level or air pockets in the cooling system
4. Radiator fan running permanently because of a control or relay fault
5. High resistance in the sensor wiring or connector
6. Wrong or poor quality replacement sensor fitted

Can you drive with it?

Driving is possible, but the engine runs cold with higher consumption and increased wear; repair soon.