Engine low on coolant
Faulty Engine Coolant Temperature (ECT) Sensor
Engine Coolant Temperature Sensor harness is open or shorted
Engine Coolant Temperature Sensor circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
This Diagnostic Trouble Code (DTC) is stored in the Engine Control Module (ECM) when the output from the Engine Coolant Temperature (ECT) Sensor is not as expected or missing. The ECM uses information from the intake air temperature sensor and the engine oil temperature sensor to carry out a plausibility check on the signal. ECT sensors are normally a negative temperature coefficient thermistor. The signal voltage drops as the engine temperature increases. The signal from the sensor is used to adjust the ignition system rate of advance and the fuel injection system from various operating conditions.