Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

DIAGNOSIS
A Tech 1 scan tool displays the engine temperature in degrees Celsius and Fahrenheit. After the engine is started, the temperature should rise steadily to about 90°C (194°F) then stabilize when the thermostat opens. If the engine has not run for several hours (overnight) the Engine Coolant Temperature (ECT) and Intake Air Temperature (IAT) temperatures should be close to each other. A fault in the ECT sensor circuit should set a Diagnostic Trouble Code (DTC) 14 or DTC 15.