P0089

DTC P0089

CIRCUIT DESCRIPTION
The engine control module (ECM) uses commanded fuel pump flow to determine a desired fuel rail pressure (FRP). The actual fuel pressure is monitored using the FRP sensor. If the FRP sensor indicates a pressure more than 20 MPa greater than desired, DTC P0089 will set.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0089 Fuel Pressure Regulator Performance

CONDITIONS FOR RUNNING THE DTC
- DTCs P0192, P0193, P0642 or P0643 are not set.
- The ignition is ON.

CONDITIONS FOR SETTING THE DTC
- The difference between the actual FRP and the desired FRP is more than 20 MPa.
- The commanded fuel pump flow is 100 mm�/second or less.

ACTION TAKEN WHEN THE DTC SETS - CALIFORNIA
- 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.

ACTION TAKEN WHEN THE DTC SETS - FEDERAL
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The MIL will not illuminate.
- 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 driver information center (DIC), if equipped, may display a message.

CONDITIONS FOR CLEARING THE MIL/DTC - CALIFORNIA
- The control module turns OFF the 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.
- Use a scan tool in order to clear the MIL and the DTC.

CONDITIONS FOR CLEARING THE DTC - FEDERAL
- 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.
- Use a scan tool in order to clear the DTC.

DIAGNOSTIC AIDS
- There are no driveability concerns associated with the FRP regulator unless a DTC is present. The most likely cause of this DTC is a sticking FRP regulator.
- If the fuel system pressure is actually too high, a fuel knock and smoke condition will exist.

TEST DESCRIPTION

Steps 1-12:

Step 13:

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