Engine Oil Pressure Switch

The PCM provides a reference voltage to the engine oil pressure switch when the ignition key is in the RUN position. With the engine running and low or no oil pressure, the engine oil pressure switch closes. The PCM detects the low reference voltage and the IPC illuminates the low oil pressure warning indicator. With the engine running and sufficient oil pressure, the engine oil pressure switch opens, sending the reference voltage high and the IPC turns off the low oil pressure warning indicator.