Circuit/System Description

The engine oil pressure switch is a two wire switch that opens and closes based on engine oil pressure. The engine control module (ECM) supplies a 12 volt signal to the switch. The switch also has a ground. The ECM monitors the signal circuit to determine if the switch is opened or closed. When the engine oil pressure is low, the switch is closed and voltage on the signal circuit is low. When the engine oil pressure is normal, the switch is open and voltage on the signal circuit is high. The ECM sends the engine oil pressure information via serial data to the body control module (BCM). The BCM then sends the engine oil pressure information to the instrument cluster via serial data. The instrument cluster will illuminate the oil pressure indicator when engine oil pressure is low.