Engine Coolant Temperature Sensor - Radiator Outlet
The radiator outlet ECT sensor is located in the radiator lower hose. The ECT sensor is push fit in the radiator lower hose and rotated clockwise to lock in position.
The radiator outlet ECT sensor circuit consists of a voltage divider which incorporates a temperature sensor. The temperature sensor is a Negative Temperature Coefficient (NTC) resistor type sensor. The input to the sensor is a 5V reference voltage supplied through a resistor within the PCM . The ground from the sensor is also connected to the PCM which measures the voltage across the sensor. As the engine coolant temperature rises the resistance of the sensor decreases and vice versa. The PCM calculates the coolant temperature from a map of sensor voltage against temperature.
In the event of the radiator outlet ECT sensor signal failure, the PCM applies a default value of 60°C (140°F) engine coolant temperature. On the second consecutive trip with a sensor fault, the PCM illuminates the Malfunction Indicator Lamp (MIL).
For additional information, refer to: ELECTRONIC ENGINE CONTROLS