SFI SYSTEM, Diagnostic DTC:P0087

DTC Code DTC Name
P0087 Fuel Rail / System Pressure - Too Low

DESCRIPTION

The cylinder fuel injection method high-pressure fuel system consists of the spill control valve, pump plunger and check valve. The spill control valve adjusts the discharge amount of the high-pressure fuel, the pump plunger operated by the camshaft pressurizes fuel, the check valve mechanically opens and closes the line to the fuel delivery pipe. The fuel pump for high pressure is installed to the cylinder head cover (bank 1 and bank 2) and is driven by the cam located at the rear end of the intake camshaft. When the plunger moves up and down by the camshaft rotations, it pressurizes the fuel. The pressurized fuel then pushes open the check valve, and the fuel flows to the fuel delivery pipe. The ECM controls the spill control valve to adjust the fuel pressure to 4 to 13 MPa (41 to 133 kgf/cm2). The ECM receives signals from the fuel pressure sensor, monitors the fuel pressure, and maintains the target fuel pressure. If the fuel pressure of the fuel delivery pipe exceeds 15.3 MPa (156 kgf/cm2), the fuel relief valve opens and returns the fuel to the fuel tank.

A0161NNE01
DTC No. DTC Detection Condition Trouble Area
P0087

Even though ECM commands fuel pump for high pressure to open spill control valve, fuel pressure decreases 5 MPa (51.0 kgf/cm2, 725 psi) from target pressure for more than 10 seconds

(1 trip detection logic)

  • Fuel leaks

  • Fuel pipe (Fuel tank - Fuel pump for high pressure [bank 1 or bank 2])

  • Fuel pipe (Fuel pump for high pressure - Fuel injector [for direct injection])

  • Fuel injector (for direct injection)

  • Fuel relief valve

  • Fuel pump for low pressure

  • Fuel pump for high pressure (bank 1)

  • Fuel pump for high pressure (bank 2)

  • Injector driver (No. 1)

  • Injector driver (No. 2)

  • ECM

MONITOR DESCRIPTION

If the fuel pressure decreases even after the ECM commands the high-pressure fuel pump to close the spill control valve, a DTC is output.

INSPECTION PROCEDURE

Tech Tips


  • Bank 1 refers to the bank that includes the No. 1 cylinder*.

    *: The No. 1 cylinder is the cylinder which is farthest from the transmission.

  • Bank 2 refers to the bank that does not include the No. 1 cylinder.

  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


  1. CHECK FUEL LEAK (HIGH OR LOW PRESSURE SIDE)


    1. Check around and beneath the car for fuel leaks, fumes, etc.

      OK
      No fuel leaks present.

    NG

    REPAIR OR REPLACE FUEL LEAK POINT

    OK

  2. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0087)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Enter the following menus: Powertrain / Engine / DTC.

    4. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P0087 A
      P0087 and other DTCs B

      Tech Tips

      If any DTCs other than P0087 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  3. CHECK FUEL PRESSURE (LOW PRESSURE)


    1. Check the fuel pressure Click here.


    NG

    CHECK AND REPLACE FUEL SYSTEM (FOR LOW PRESSURE)

    OK

  4. CHECK MISFIRE COUNT


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Start the engine.

    4. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Direct.

    5. Allow the engine to idle.

    6. Monitor all of the misfire rate values that are displayed on the tester: Powertrain / Engine / Data List / All Data / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

      If no misfire counts occur for any of the cylinders, perform the following procedure:


      1. Move the shift lever to the D position.

      2. Monitor all of the misfire count values that are displayed on the tester.

        Result
        Misfire Count Proceed to
        No misfire counts, or misfire counts occur randomly in all cylinders A
        Misfire counts occur in particular cylinder B

    B

    REPLACE FUEL INJECTOR FOR DIRECT INJECTION Click here

    A

  5. INSPECT FUEL RELIEF VALVE


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Start the engine.

    4. Enter the following menus: Powertrain / Engine / Data List / Fuel Press.

    5. Record the Fuel Press value.

    6. Turn the engine switch off.

    7. Wait for 10 seconds.

    8. Turn the engine switch on (IG) and turn the tester on.

    9. Enter the following menus: Powertrain / Engine / Data List / Fuel Press.

    10. Compare the Fuel Press value recorded with engine running to the Fuel Press value currently shown on the tester.

      Result
      Inspection Result Proceed to
      Fuel Press value is maintained A
      Fuel Press value drops B

    B

    REPLACE FUEL RELIEF VALVE Click here

    A

  6. CHECK FUEL PRESSURE (HIGH PRESSURE)


    1. Check the fuel pressure Click here.


    NG

    REPLACE FUEL PUMP ASSEMBLY (FOR HIGH PRESSURE) Click here

    OK

  7. INSPECT INJECTOR DRIVER (NO. 1 AND NO. 2)


    1. Turn the engine switch off.

    2. Replace the No. 1 and No. 2 injector drivers with known good ones.

      Note

      Do not disconnect and reconnect the connectors with the engine switch on (IG), as the injector driver (EDU) may be damaged.

    3. Connect the intelligent tester to the DLC3.

    4. Start the engine.

    5. Clear the DTCs Click here.

    6. Perform the driving test.

    7. Enter the following menus: Powertrain / Engine / DTC.

    8. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P0087 A
      No output B

    B

    REPLACE INJECTOR DRIVER (NO. 1 OR NO. 2) Click here

    A

  8. REPLACE FUEL PUMP (FOR HIGH PRESSURE OF BANK 1 AND BANK 2)


    1. Replace the fuel pump (for high pressure of bank 1 and bank 2) Click here.


    NEXT

  9. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Clear the DTC Click here.

    4. Start the engine.

    5. Perform the driving test.

    6. Enter the following menus: Powertrain / Engine / DTC.

    7. Read DTCs.

      Result
      Display (DTC Output) Proceed to
      P0087 A
      No output B

    B

    END

    A

    REPLACE ECM Click here