Engine Coolant Temperature Sensor 1 Circuit Range/Performance
The coolant temperature sensor tells the ECU how hot the engine is. With that it adjusts starting, the mixture, the fan and the gauge on the dashboard.
What the car has detected
The temperature the sensor gives does not change as it should: for example it jumps suddenly or does not rise with the engine running.
It is not usually dangerous straight away, but if the sensor fails the fan may not switch on and the engine may overheat. Watch the temperature gauge and have it checked soon.
Symptoms
- Engine warning light on
- Temperature gauge that goes up and down or does not move
- Hard cold starts or higher fuel use
Possible causes
- Faulty coolant temperature sensor
- Loose or corroded connector
- Thermostat stuck open
- Low coolant or air in the system
Checks for the garage
- Check the coolant level with the engine cold
- Compare the live data reading with the expected one
- Check the thermostat if the engine takes long to warm up
Next step
Ask for the coolant temperature sensor, its connector and the thermostat to be checked.
Go to a garage in the next few days. If the gauge reads very hot or there is steam, stop the car in a safe place.