General Information

Engine Control
P0088 Fuel Rail/System Pressure - Too High - General Information

Component Location





General Description

GDI PCM operates fuel pressure regulator (spill valve) with the signal from fuel rail pressure sensor to control optimized RPM and rail pressure. But PCM shows this DTC and enters limp home mode limiting fuel mass and maximum RPM in order to prevent abnormal control of PCM under the bad condition out of target rail pressure range.
Rail pressure monitoring error DTC shows indirectly the status of low pressure fuel and mechanical operating status of high pressure pump and fuel pressure regulator with the signal of rail pressure sensor and fuel pressure regulator.

DTC Description

The PCM sets DTC when the actual rail pressure is higher than the target pressure.

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data












Fig.1) Normal waveform of rail pressure sensor at idle.
Fig.2) Normal waveform of rail pressure sensor at acceleration.