Toyota 89422-20010 Sensor, Water Temperature

You can Select Your Vehicle to check if 89422-20010 fits your vehicle.

Shut off the engine and connect the wire at the sending unit to a clean ground on the engine. If the gauge now indicates hot, replace the sending unit. If the gauge still does not work, there may be an open circuit or a faulty gauge.

The fuses should be checked if the gauge is inoperative.

If the coolant temperature gauge is not working, start by checking the fuses. In case the gauge indicates hot as soon as the engine is started cold, disconnect the wire at the coolant temperature sending unit. If the gauge reading drops, replace the sending unit. If the reading remains high, there may be a short circuit or a faulty gauge. If the gauge fails to show any indication after the engine has warmed up, and the fuses are fine, shut off the engine and disconnect the wire at the sending unit. Use a jumper wire to connect it to a clean ground on the engine and briefly turn on the ignition. If the gauge now indicates hot, replace the sending unit. If the gauge still doesn't work, there may be an open circuit or a faulty gauge. To replace the sending unit, ensure the engine is completely cool. Apply thread sealant or Teflon tape to the threads of the new sending unit. Loosen the radiator cap, squeeze the upper radiator hose, and then tighten the cap to create a slight vacuum in the cooling system. Unplug the electrical connector and unscrew the switch. Immediately install the new switch and tighten it securely. Plug in the electrical connector. Check the coolant level, add coolant if necessary, and start the engine to check for coolant leakage and gauge operation.

To troubleshoot issues with the coolant temperature gauge, start by checking the fuses if the gauge is inoperative. If the temperature indicator shows excessive temperature after running for a while, it may indicate a problem. In the case where the gauge indicates "Hot" shortly after starting the engine cold, disconnect the wire at the coolant temperature sending unit. If the gauge reading drops, replace the sending unit. If the reading remains high, there may be a shorted wire to the gauge or a faulty gauge. If the coolant temperature gauge fails to indicate after the engine has warmed up and the fuses are fine, shut off the engine. If the gauge still doesn't work, there may be an open circuit or a faulty gauge. For replacement, start by releasing any pressure in the radiator by removing and reinstalling the cap when the engine is cool. Disconnect the electrical connector from the sending unit and apply sealant to the threads of the new sending unit. Unscrew the old sending unit and quickly install the new one to prevent coolant loss. Tighten the sending unit securely and connect the wiring harness. Refill the cooling system, run the engine, and check for leaks and proper gauge operation.

The new unit should be installed and tightened securely. Thread sealant should not be used as it may electrically insulate the sending unit.

The engine coolant temperature (ECT) sensor utilizes a thermistor, which is a resistor that adjusts its resistance in response to temperature changes. This variation in resistance directly affects the voltage signal transmitted from the sensor to the PCM. When the sensor temperature decreases, the resistance values increase, and as the temperature rises, the resistance values decrease. Any issues with the ECT sensor circuits will trigger a diagnostic trouble code. To check the ECT sensor, begin by measuring its resistance. Disconnect the electrical connector and use an ohmmeter to measure the resistance between the sensor's terminals. At room temperature (68 degrees F), the resistance should be between 2,500 and 3,000 ohms. Start the engine and monitor the resistance or warm the sensor in a pan of water. At 180 degrees F, the resistance should decrease to approximately 250 to 300 ohms. If the test results are incorrect, it is necessary to replace the ECT sensor. For ECT sensor replacement, ensure the ignition key is in the OFF position and drain around one gallon of coolant from the cooling system. Wrap the threads of the new sensor with Teflon sealing tape to prevent leakage and thread corrosion. Disconnect the electrical connector and carefully unscrew the sensor. Installation involves following the reverse steps of the removal process and refilling the cooling system.

This part goes into a water jacket on the engine block

This sensor reads the temperature of the coolant