What to know about the Coolant Temperature Switch (Sensor):
The coolant temperature switch, also known as the coolant temperature sensor, is a switch that reads the engine coolant temperature and sends a signal to the engine control module, or ECM, to control other functions of engine operation such as the air-fuel ratio.
It is also called a switch because on some cars, it is used to turn on the engine cooling fan at a specific temperature. This aids in the engine warm-up process as well as keeping the engine at a safe operating temperature.
Facts to Note:
The coolant temperature switch is a vital part of the cooling system. If defective, it can cause severe internal engine damage due to overheating, incorrect air-fuel ratio, or incorrect ignition timing. It can also cause shorter life to the cooling fan motor or other electrical devices of the cooling system.
Some vehicles are furnished with a separate sensor to display the engine temperature to the driver via the temperature gauge.
How to Fix:
The Coolant Temperature Switch is confirmed that it needs to be changed. The coolant is drained until the switch is exposed.
The faulty Coolant Temperature Switch is removed by disconnecting the connector and removing it from the manifold.
The new Coolant Temperature Switch is fixed into the mounting hole in the manifold and the electrical connector is reconnected. The coolant is then refilled.
The Coolant Temperature Switch is tested for operation, codes cleared, and retested to ensure all codes have been resolved.
The vehicle is road tested to make sure proper operation of the Cooling System.
If you suspect that your coolant temperature switch has failed, have one of your licensed mechanics come out straightaway to analyze the problem.
Common symptoms indicating you may need to change Coolant Temperature Switch (Sensor):
Check Engine light on
Cooling fan runs erratically
Engine misfires, stalls, or idles roughly
Intermittent coolant temperature
Importance of this service:
This part, when defective, could cause the fan to run erratically or not at all, which in turns causes overheating or overuse of the cooling fan motor. Whenever overheating occurs, severe engine damage is a possibility.
The engine air-fuel ratio is what keeps it running smoothly. If the ratio gets skewed, the engine will have poor fuel economy and run poorly or not at all. The coolant temperature switch is essential because it gives the ECM the information it needs to make this calculation and run the engine optimally.