Subaru-s hand-held tester or an equivalent OBD-II scan tool must be used in order to check the operation of the coolant temperature sensor. For the detailed operation procedures, refer to the OBD-II General Scan Tool instruction manual.
Start the car and allow it to run to normal operating temperature. If the scan tool data shows the temperature less than 140°F (60°C), the sensor should be replaced.
- Turn the ignition switch to OFF.
- Disconnect the connector from the sensor.
- Turn the ignition switch ON.
- Using the Subaru scan tool, read the sensor signal data. If the measured value is less than -40 degrees F, replace the sensor.