Circuit/System Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the engine oil pressure (EOP) sensor. When the oil pressure is high, the sensor is open, and the ECM/PCM senses a high signal voltage. When the oil pressure is low, the sensor is closed, and the ECM/PCM senses a low signal voltage.