Fuel Pressure Sensor: Description
WARNING: This page is about a different car, the 2006 Dodge Sprinter. However, it is still accessible from the selected car via links, so may be relevant.
The fuel rail pressure sensor measures the current fuel rail pressure and supplies an appropriate voltage signal to the ECM. The non-constant fuel system pressure influences the position of the internal diaphragm. This results in a variation in the electrical resistance which is analyzed by the ECM.