The FRP sensor is like a diaphragm which calculates the pressure changes between the atmospheric pressure and the fuel rail, and sends a signal to the PCM (Powertrain Control Module) that corresponds to the reading of the pressure of the rail gas.
The Power Train Control Module (PCM) uses this signal to control the injection time and the correct impulse amplitude for the required fuel supply under speed and load conditions.
With the fuel volume regulator, the Fuel Rail Pressure Sensor (FRP) establishes a closed-loop fuel pressure control system. In the event that this sensor has an electrical fault, the result is that the fuel injection pump is deactivated.