General Information

Engine Control
P0091 Fuel Pressure Regulator 1 Control Circuit Low - General Information

Component Location





General Description

GDI ECM operates fuel pressure regulator (spill valve) with the signal from fuel rail pressure sensor to control optimized RPM and rail pressure.
High pressure pump adds high pressure to low pressure fuel from low pressure pump. Controling fuel pressure is done by fuel pressure regulator from 40 to 150 bar. Under the abnormal condition of high pressure fuel system, ECM contols fuel system as low pressure.

DTC Description

When ECM detects short to ground in the spill valve control circuit, ECM sets DTC P0091.

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data




Fig.1) Normal waveform of spill valve at idle.