Oil Pressure Sensor
The oil pressure sensor is mounted in oil filter adapter and serves two purposes. One is to measure changes in oil pressure and other is to serve as a backup system to PCM and fuel pump relay to energize fuel pump. At low pressures oil pressure sensor resistance is high and at high pressures sensor resistance is low. The BCM supplies a 5 volt reference signal and ground to sensor and measures voltage signal as it is changed by sensor. The voltage is close to 5 volts at low pressure and close to 0 volt at high pressure. The oil pressure sensor also has a set of normally open switch contacts that close when oil pressure builds above 28 kPa (4psi). These contacts will energize fuel pump in event of a PCM and/or fuel pump relay failure. See Fig 1 .