Oil Pressure Sensor: Description and Operation

As a backup system to the fuel pump relay, the fuel pump also can be turned "ON" by the fuel pump and engine oil pressure switch. The switch has two internal circuits. One operates the oil pressure indicator or gauge in the instrument cluster and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump and engine oil pressure switch runs the fuel pump.