Oil Pressure Sensor: Description and Operation

Fuel Pump Relay & Oil Pressure Switch Circuit Diagram:

Oil Pressure Sensor Removal:

After the engine starts (ignition pulses being received and engine speed greater than 500 rpm), the ECM turns the fuel pump relay "OFF", and power is supplied to the fuel pump through a switch in the oil pressure sensor. The fuel pump switch in the oil pressure sensor is normally "OPEN" and closes when there is sufficient oil pressure. If the oil pressure should fall below the critical level while the engine is running, the switch opens and the fuel pump turns "OFF" and the engine will die. This is to stop the engine from running without oil pressure and help prevent engine damage.