Monitor Description

The Engine Coolant Temperature (ECT) sensor is used to monitor the engine coolant temperature. The ECT sensor has a thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in the resistance are reflected in the voltage output from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature. If the sensor output voltage deviates from the normal operating range, the ECM interprets this deviation as a fault in the ECT sensor and sets the DTC.

Examples:

1. Upon starting the engine, the ECT is between 35°C (95°F) and 60°C (140°F). If after driving for 250 seconds, the ECT remains within 3°C (5.4°F) of the staring temperature, the DTC is set (2 trip detection logic).
2. Upon starting the engine, the ECT is over 60°C (140°F). If after driving for 250 seconds, the ECT remains within 1°C (1.8°F) of the starting temperature, the DTC is set (6 trip detection logic).