Engine Controls - Tests W/Codes

Engine oil temperature sensor is a thermistor, similar to a coolant or air temperature sensor. When engine oil temperature is cold, sensor resistance is high and PCM will see a high monitored voltage signal on engine oil temperature sensor signal terminal. As temperature increases, resistance decreases and PCM sees a lower monitored voltage on circuit. Code 52 will set if engine oil temperature sensor is less than -31°F (-35°C) and engine has been running for more than 30 minutes.