There are two engine coolant temperature sensors, an upper one located in the coolant outlet housing on 1.4L models or in the thermostat housing on 1.8L models, and a lower one mounted in the lower right side of the radiator on both models. Begin by turning the ignition key to OFF and draining the cooling system. For the engine-mounted ECT sensor on 1.4L models, remove the charge air cooler outlet pipe, disconnect the electrical connector from the ECT sensor, which is situated in the coolant outlet housing or thermostat housing, pull out the retaining clip, and twist and pull the sensor from its bore. Installation is the reverse of removal, ensuring the retaining clip is fully seated, followed by refilling the cooling system. For the radiator-mounted ECT sensor, remove the front bumper cover, locate the sensor on the right side of the radiator, disconnect the sensor electrical connector, remove the retaining clip, and pull the sensor from the radiator. Again, installation is the reverse of removal, ensuring the retaining clip is fully seated, and then refill the cooling system.