Engine Coolant Temperature Sensor

The Engine Coolant Temperature (ECT) sensor is located at rear of cylinder head, in coolant housing (2.0L), or at rear of left cylinder head (2.5L). 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.