This fuel pressure sensor monitors the pressure in the fuel system and sends a signal to the engine control unit. It is mounted on the fuel rail or supply line, where it provides real-time data that the ECU uses to adjust injection timing and fuel volume. A failing sensor can cause hard starting, erratic idle, or a loss of power under load. As an original-manufacturer component, it matches the electrical connector geometry and the pressure-response curve of the assembly it replaces, so no recalibration of the ECU is needed.