Circuit/System Description

The engine oil temperature (EOT) sensor is a variable resistor. The EOT sensor measures the temperature of the engine oil. Monitoring the engine oil temperature input is necessary for optimal control of the cam phasers. The oil temperature is monitored from dual function oil level switch and temperature sensor located in the oil pan. The EOT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies bias 5 volts on the EOT signal circuit, and a ground for the EOT low reference circuit. When the EOT sensor is cold, the sensor resistance is high. When the engine oil temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the EOT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the EOT signal circuit.