Engine Coolant Temperature Sensor

The Engine Coolant Temperature (ECT) sensor is located at front of intake manifold, near thermostat housing (1.6L), or at rear of cylinder head, in thermostat housing (2.0L). ECT sensor thermistor changes resistance with respect to temperature. High temperature causes low resistance. Low temperature causes high resistance. A reference voltage (supplied and monitored by PCM) is modified by sensor resistance. PCM uses this information to control operation of various devices.