There are many different types of temperature sensors on the vehicle, such as Exhaust Gas Temperature, Coolant Temperature Sensor, Ambient temperature sensor, Intake Air Temperature Sensor, Fuel Temperature Sensor, Temperature Switch, Urea(Adblue) Temperature Sensor, Retarder Temperature Sensor, Temperature Alarm, Intercooler Temperature Sensor and so on..
Exhaust Gas Temperature Sensor is used to measure the temperature of the Gas that exhausted from the engine, while the temperature reach the working status, the SCR system begin to work.
Coolant Temperature Sensor is used to measure the temperature of the coolant, while the temperature of the coolant is too high. An alarm will display on the Meter. Someone take water instead of coolant, so , sometimes coolant temperature sensor is called water temperature sensor.
Intake Air Temperature sensor is used to measure the temperature of the air flowing into engine. It will tell the ECU how to work and make the engine work better.