Monitor Description

The engine coolant temperature sensor is used to monitor the engine coolant temperature. The 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 in the thermistor increases. When the temperature is high, the resistance decreases. These variations in 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. When the sensor output voltage deviates from the normal operating range, the ECM determines that there is a malfunction in the sensor and sets the DTC.

Example:

If the ECM estimates that the engine coolant temperature is less than -40°C (-40°F) or more than 140°C (284°F) and either condition continues for 0.5 seconds or more, the ECM sets the DTC.

If the causes of a malfunction are not eliminated by repairs, the DTC is set again 0.5 seconds after the engine is next started.