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

SCAN TOOL TESTING
A scan tool displays the engine temperature in degrees Celsius. 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 been run for several hours (overnight), the ECT and AT temperatures should be close to each other hard fault in the ECT sensor circuit should set either a DTC P0117 or P0118. An intermittent failure in the ECT sensor circuit should set either a P1114 or P1115. The DTC charts also contain a chart to check for sensor resistance values relative to temperature.