Coolant Temperature Sensor/Switch (For Computer): Description and Operation

ECT SENSOR










Component Description
The engine coolant temperature sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

RADIATOR COOLANT TEMPERATURE SENSOR










Component Description
The radiator coolant temperature sensor is installed on the radiator lower tank and used to detect the radiator coolant temperature. The sensor modifies a voltage signal from the ECM and returns the modified signal to the ECM as the radiator coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of thermistor decreases as temperature increase. The ECM uses this signal to control the cooling fan speed control solenoid valve.

CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.