This checking procedure applies only to 2006 and earlier models, as 2007 and later models require special equipment and procedures. The Engine Coolant Temperature (ECT) sensor is located at the front left corner of the cylinder head on 2010 and earlier 1.8L and 2012 and earlier 2.0L models, while on 2011 and later 1.4L models and all 2013 and later models, it is found on the driver's side end of the cylinder head. Begin by draining the cooling system and, for 1.4L and 1.6L models, removing the air filter housing. Next, move the wiring harness and vacuum lines out of the way, then unplug the electrical connector from the ECT sensor by prying up the wire retainer and pulling the connector off. For all models except 1.4L, unscrew and remove the ECT sensor; for 1.4L models, remove the locking clip and pull the sensor out of the water temperature control housing. Suspend the ECT sensor in a container of water and heat the water while monitoring the temperature with a cooking thermometer, ensuring the sensor does not touch the sides or bottom of the container. Connect an ohmmeter to the sensor terminals and measure the resistance as the water heats, comparing the measurements with specified resistance values and replacing the sensor if there is a significant variation. Before installing the ECT sensor, ensure the brass sealing washer is in place if equipped, and for all models except 1.4L, tighten the sensor to the specified torque. For 1.4L models, lubricate the sensor with clean coolant before inserting it into the water temperature control housing until the locking clip can be installed. After installation, fill the cooling system, start the engine, and check for leaks, with installation being the reverse of removal.
