DTC P0091-00: Fuel Pressure Regulator 1 Control Circuit Low: General Description

The Fuel Pressure Control Valve (FPCV) provides a feedback signal to indicate the fuel rail pressure so the ECM can command the correct injector timing and pulse width for correct fuel delivery at all speed and load conditions.

The ECM operates the fuel pressure control valve with the signal from the fuel rail pressure sensor to control optimized RPM and rail pressure.

The high pressure pump adds high pressure to low pressure fuel from the low pressure pump. The fuel pressure regulator controls fuel pressure from 20 bar (2MPa/290.1psi) to 150 bar (20MPa/2900psi). Under the abnormal condition of high pressure fuel system, the ECM controls fuel system as low pressure.