Q: How to disconnect, remove, and replace the Engine Coolant Temperature (ECT) sensor in Lexus RX330?A: Be careful with the ECT sensor in four-cylinder models as it affects the fuel injection system. It's on the left end of the cylinder head. Disconnect the negative battery cable, partially drain the cooling system, disconnect the sensor's electrical connector, and unscrew it. Apply Teflon tape to the threads and ensure secure tightening during installation. In V6 models, the ECT sensor is on the water outlet casting on 3.0L and 3.3L engines, and under the air filter housing on 3.5L engines. Disconnect the negative battery cable, partially drain the cooling system, and disconnect the sensor's electrical connector. Depending on the model, unscrew the sensor or remove the retaining clip and pull out the sensor. Ensure proper tightening or full seating before reinserting the clip. Refill the cooling system to finish.