Circuit/System Description

The engine oil level switch is part of the engine oil level/temperature sensor. The switch is normally closed with the proper oil level in the oil pan, and opens when the oil level falls below a minimum level. The engine control module (ECM) supplies a 5 V signal and low reference to the switch. The ECM monitors the 5 V signal to determine if the engine has sufficient oil. The voltage on this circuit will be 0.5 V or less at normal oil levels, and 4.5 V or greater at low oil levels.