Fuel Pressure Sensor
WARNING: This page is about a different car, the 2008 Jeep Commander. However, it is still accessible from the selected car via links, so may be relevant.
The fuel rail pressure sensor monitors and passes on the current fuel rail pressure to the ECM. The non-constant system pressure influences the position of the sensor diaphragm which alters the sensors electrical resistance.
WARNING:
A residual pressure of about 50 to 80 bar (725 to 1160 PSI) remains in the fuel rails after switching off the engine. The high-pressure system must only be opened after the fuel pressure drops to a safe level.