Secondary Cooling System Engine Coolant Temperature 2 (ECT2) Sensor
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The secondary cooling system ECT2 sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.
The secondary cooling system ECT2 sensor is located in the exhaust gas recirculation (EGR) cooler. The secondary cooling system ECT2 sensor measures the temperature of the secondary cooling system and provides a feedback signal to the PCM. The PCM uses the secondary cooling system ECT2 sensor input to control the EGR cooler bypass valve.