P0088

DTC P0088

CIRCUIT DESCRIPTION
The engine control module (ECM) monitors fuel rail pressure (FRP) using the FRP sensor. If the sensor indicates a pressure more than the commanded rail pressure plus a possible transitional overshoot, the ECM will set diagnostic trouble code (DTC) P0088 for fuel rail pressure too high.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0192, P0193, or P0641 are not set.
- The ignition is ON.

CONDITIONS FOR SETTING THE DTC
The actual fuel pressure is more than 167 MPa.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
- The control module will limit fuel injection and fuel rail pressure.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
There are no driveability concerns associated with the fuel rail pressure regulator unless a DTC is present. The most likely cause of this DTC is a sticking fuel rail pressure regulator.

If the fuel system pressure is actually too high, a fuel knock and smoke condition will exist.

TEST DESCRIPTION

Steps 1-4:

Steps 5-9:

Steps 10-13:

The number below refers to the step number on the diagnostic table.
3. DTC P0090 is a current flow problem in the FRP regulator circuit. This incorrect current draw could lead to incorrect fuel pressure. This hardware problem should be diagnosed before the performance DTC is checked.