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

Scan Tool Diagnosis
The scan tool displays Engine Coolant Temperature (ECT) in degrees. After engine start-up, the temperature should rise steadily to about 90°C (194°F) then stabilize when thermostat opens. If the engine has not been run for several hours (overnight), the engine coolant temperature and intake air temperature displays should be close to each other.

ECT Sensor Circuit Malfunction Codes
When the PCM detects a malfunction in the ECT sensor circuit, the following Diagnostic Trouble Codes (DTCs) will set:

^ DTC P0117 circuit low. Testing and Inspection

^ DTC P0118 circuit high. Testing and Inspection

^ DTC P0125 excessive time to Closed Loop. Testing and Inspection

^ DTC P1114 circuit intermittent low. Testing and Inspection

^ DTC P1115 circuit intermittent high. Testing and Inspection

ECT Specifications
A table to check for sensor resistance values relative to temperature can be found under Specifications / Electrical. Electrical Specifications