Monitor Description
The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the engine coolant. When the engine coolant temperature becomes low, the resistance of the thermistor increases. When the temperature becomes high, the resistance drops. These variations in the resistance are reflected in the voltage output from the engine coolant temperature sensor.
The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature. If the sensor voltage output deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the engine coolant temperature sensor and sets the DTC.
Examples:
- Upon starting the engine, the engine coolant temperature is between 35°C and 60°C (95°F and 140°F). If the engine coolant temperature remains within 3°C (37°F) of the stating temperature after driving for 250 seconds, the DTC is set (2 trip detection logic).
- Upon starting the engine, the engine coolant temperature is over 60°C (140°F). If the engine coolant temperature remains within 1°C (34°F) of the starting temperature after driving for 250 seconds, the DTC is set (6 trip detection logic).