Engine Coolant Temperature (ECT) Sensor

Engine Coolant Temperature (ECT) Sensor:

Engine Coolant Temperature (ECT) Sensor:

The Engine Coolant Temperature (ECT) sensor is located in the cylinder head near the ignition distributor. The ECT sensor is a thermistor (a variable resistor that changes value when the temperature changes). The ECT sensor is connected in series with a fixed resistor in the Powertrain Control Module (PCM). The PCM applies 5 volts to the ECT sensor.

The PCM monitors the voltage drop across the ECT sensor and converts the voltage reading into a temperature value. The ECT sensor voltage reading at the PCM will vary with the changes in the engine temperature.