Common Rail PRESSURE SENSORS Fuel high pressure sensor Diesel CR pressure sensor, commonly referred to as the fuel pressure sensor, it is installed at one end of the oil rail to measure the fuel pressure in the common rail pipe. Fuel Rail Pressure Sensor 499000-6100 is a part of vehicle’s fuel system and designed to monitor the fuel pressure that is present at the fuel rail. It sends this signal to the ECU, which then uses it to make adjustments to the vehicle’s fuel and timing.