Fuel Pressure Sensor/Switch: Description and Operation

The fuel pressure sensor senses the pressure difference between the fuel
injection supply manifold and the intake manifold, and provides the powertrain control module with the current fuel injection supply manifold pressure. The return fuel line to the fuel tank has been deleted in this type of fuel system. The differential fuel intake manifold press together with inferred fuel temperature provides an indication of the fuel vapors in the fuel rail.

The power train control module uses this information to vary the duty cycle output to the Fuel Pump Driver Module (FPDM) which controls the speed of the fuel pump. The speed of the fuel pump sustains fuel injection supply manifold pressure which preserves fuel in its liquid state.

The dynamic range of the fuel injectors increase is due to the higher pressure, which allows injector pulse width to decrease.