DTC Advanced Diagnostics: P0088
DTC P0088:Fuel Rail Pressure Too High

General Description

The high pressure fuel system consists of a fuel rail, a fuel rail pressure sensor, a high pressure fuel pump with a built-in fuel control solenoid. In dependence of torque demand and engine speed, high pressure has to be adjusted. Therefore the fuel pressure in the rail is measured and controlled with help of the fuel control solenoid. If the difference between the desired and measured fuel rail pressure is too large, combustion and emissions can be influenced. The powertrain control module (PCM) monitors the high pressure fuel control system. The diagnosis checks if the controller is able to adjust the required rail pressure based on the set point. If the measured fuel pressure is greater than the set point, the difference of these two values is negative. If the negative difference is less than a specified value, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
5 seconds or more
DTC Type
One drive cycle, MIL on

Enable Conditions
Condition
Minimum
Maximum
Elapsed time after starting the engine
5 seconds
–

Malfunction Threshold
The fuel rail pressure negative deviation from the set point is less than -2,000 kPa (-20.4 kgf/cm2, -290 psi).

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes
High pressure fuel pump failure
Fuel rail pressure sensor drifting

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.