Circuit/System Description

The engine control module (ECM) monitors the engine oil temperature sensor with a low reference circuit and signal circuit. The ECM monitors the voltage drop across the sensor, which is inversely proportional to temperature. When the ambient air temperatures are cold, the resistance of the sensor is high and the voltage signal is high. When the ambient air temperatures are hot, the resistance of the sensor is low and the voltage signal is low. The ECM converts the data from the engine oil temperature sensor to a engine oil temperature signal. The ECM sends the engine oil temperature signal to the instrument cluster via serial data. The instrument cluster displays the engine oil temperature based on the information from the ECM.