Fuel Rail Pressure Sensor
The fuel rail pressure sensor signals the pressure in the fuel rail to the ECU .
The fuel rail contains a pressurized supply of diesel fuel ready for the fuel injectors to use. When the pressure in the fuel rail drops the fuel pressure sensor signals this to the ECU and the pressure produced by the fuel injection pump is restored. The ECU controls the supply of fuel to the rail from the high pressure pump; it does this by means of a Fuel pressure control valve. If the fuel pressure sensor fails or becomes faulty run a diagnostic check on the vehicle.