Fuel Pressure Regulator: Description and Operation
PRESSURE REGULATOR ASSEMBLYThe pressure regulator assembly is a diaphragm operated relief valve with fuel pump pressure on one side, and regulator spring pressure on the other side. The regulator maintains a constant pressure differential across the fuel injectors at all times by the amount of pressure it takes to lift the diaphragm off its seat.
Spring pressure controls fuel pressure. This spring is preset at the factory and no adjustment is required. The fuel pressure regulator is located on the fuel secondary fuel pump module inside the fuel tank.
With ignition in On position and engine Off, fuel pressure at pressure test connection should be approximately 400 kPa (54 psi). If pressure is lower than specification, excessive odor and DTC P0172, P0175 may set. Refer to "Fuel System Testing".