Circuit/System Description
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
High pressure fuel is regulated by the fuel rail pressure (FRP) regulator mounted on the fuel injection pump. The FRP regulator is controlled by the engine control module (ECM). The FRP regulator has a solenoid supply voltage circuit and solenoid control circuit. The ECM monitors the current on the circuits to detect a failure.