Toyota 89422-16010 Sensor, Water Temperature

To replace a coolant temperature sensor, start by allowing the engine to cool down and then slowly remove the radiator cap to release the pressure in the cooling system. If a new sensor is being fitted, there is no need to drain the system, but if the sensor will be left out for some time, a plug should be inserted to prevent coolant loss. Disconnect the sensor wiring plug and unscrew the sensor, making sure to recover the O-ring seal if applicable. When refitting, tighten the sensor securely and ensure the connector seal is in place before connecting the wiring. Finally, refill or top-up the cooling system as needed. It is important to note that all models have a temperature display warning light, with blue indicating a cold engine and red indicating a hot engine.

The ECT sensor is a thermistor that sends a voltage signal to the PCM, which is affected by changes in resistance values as the sensor temperature increases or decreases.