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Home >> Lexus >> 2008 >> GS 450h >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTC P0010 - P0128 >> DTC P0088 Fuel Rail / System Pressure - Too High >> Inspection Procedure

Inspection Procedure

HINT:

Read freeze frame data using the Techstream. 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 (See FREEZE FRAME DATA ).

  1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0088) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG) and turn the Techstream on.
    3. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    4. Read the DTCs using the Techstream.

    Result 

    RESULT REFERENCE

    Display (DTC Output) Proceed to
    P0088 A
    P0088 and other DTCs B

    HINT:

    If any codes other than P0088 are output, perform troubleshooting for those DTCs first.

    B:  GO TO DTC CHART

    A: Go to next step 

  2. PERFORM ACTIVE TEST USING TECHSTREAM (FP REL VLV) 
    1. Put the engine in inspection mode (See INSPECTION MODE PROCEDURE ).
    2. Warm up the engine.
    3. Connect the Techstream to the DLC3.
    4. Turn the Techstream on.
    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press and Coolant Temp and Battery Voltage.
      NOTE:
      • Coolant Temp value is 50°C (122°F) or more
      • Battery Voltage value is 10 V or more
      • Fuel Press value is 2 MPa or more
    6. Turn the power switch off.
    7. Wait for 10 seconds.
    8. Put the engine in inspection mode.
    9. Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
    10. After starting the engine, turn the power switch off within 45 seconds.

      HINT:

      Before turning the power switch off, write down the Fuel Press value.

    11. Wait for 10 seconds. Then turn the power switch on (IG).
    12. Enter the following menus: Powertrain / Engine and ECT / Active Test / Fuel Pressure Relief Valve open / Fuel Press and Coolant Temp and Battery Voltage.
    13. Before turning the power switch off, check if the Fuel Press value is stable.

      HINT:

      Before performing the Active Test, check that the following conditions are met.

      • Coolant Temp value is 50°C (122°F) or more
      • Battery Voltage value is 10 V or more
      • Fuel Press value is 2 MPa or more
    14. Set Fuel Pressure Relief Valve Open to ON and open the fuel relief valve.
      NOTE:
      • Wait 30 seconds after turning the power switch on (IG). If ON Is selected before 30 seconds have passed, the Active Test will not operate.
      • After selecting ON, the Active Test will turn off automatically after 2 seconds have passed.
      • After ON is selected, ON will not be operable for 60 seconds.
    15. After performing the Active Test, check the fuel pressure.
    Fig 1: Active Test Performance For Fuel Pressure
    G05813331Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Result 

    RESULT REFERENCE

    Inspection Result Proceed to
    During Active Test, fuel pressure drops A
    During Active Test, fuel pressure does not change B

    B:  Go to step  6

    A: Go to next step 

  3. REPLACE FUEL PUMP (FOR HIGH PRESSURE) 
  4. CHECK IF DTC OUTPUT REOCCURS (SEE IF DTC P0088 IS OUTPUT AGAIN) 
    1. Clear DTCs (See DTC CHECK / CLEAR ).
    2. Put the engine in inspection mode (See INSPECTION MODE PROCEDURE ).
    3. Connect the Techstream to the DLC3.
    4. Turn the Techstream on.
    5. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    6. Read the DTCs using the Techstream.

    Result 

    RESULT REFERENCE

    Display (DTC Output) Proceed to
    P0088 A
    No output B

    B: END 

    A: Go to next step 

  5. PERFORM ACTIVE TEST USING TECHSTREAM (TARGET FUEL PRESS) 
    1. Put the engine in inspection mode (See INSPECTION MODE PROCEDURE ).
    2. Connect the Techstream to the DLC3.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Target Pressure / Fuel Press.
    5. Check that the fuel pressure fluctuates when the target fuel pressure changes.

    HINT:

    The Control the Target Press operation lowers the target fuel pressure by 12.5% or increase the target fuel pressure 25%.

    OK: 

    Fuel pressure fluctuates. 

    NG: REPLACE FUEL PRESSURE SENSOR 

    OK: REPLACE ECM 

  6. INSPECT FUSE (RELIEF VLV) 
    1. Remove the RELIEF VLV fuse from the engine room No. 1 junction block.
    2. Check the RELIEF VLV fuse resistance.

      Standard resistance: 

      Below 1 Ω 

    3. Reinstall the RELIEF VLV fuse.
      4. Fig 2: Identifying Relief VLV Fuse
      G05302307Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE 

    OK: Go to next step 

  7. INSPECT RELIEF VLV RELAY 
    1. Remove the RELIEF VLV relay from the engine room No. 1 relay block.
    2. Measure the resistance of the fuel relief valve relay.

    Standard resistance 

    TESTER CONNECTION AND SPECIFIED CONDITION

    Tester Connection Specified Condition
    3 - 5 10 kΩ or higher
    3 - 5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2)
    Fig 3: Inspecting Relief VLV Fuse
    G05302308Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE FUEL RELIEF VALVE RELAY 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (RELIEF VLV RELAY - ECM, RELIEF VLV RELAY FUEL RELIEF VALVE, FUEL RELIEF VALVE - BODY GROUND) 
    1. Remove the RELIEF VLV relay from the engine room No. 1 relay block.
    2. Disconnect the A53 ECM connector.
    3. Disconnect the E82 fuel relief valve connector.
    4. Measure the resistance.

    Standard resistance (Check for open) 

    TESTER CONNECTION AND SPECIFIED CONDITION

    Tester Connection Specified Condition
    RELIEF VLV relay (1) - DSVR (A53-3) Below 1 Ω
    RELIEF VLV relay (3) - FRI (E82-1) Below 1 Ω
    FRIO (E82-2) - Body ground Below 1 Ω

    Standard resistance (Check for short) 

    TESTER CONNECTION AND SPECIFIED CONDITION

    Tester Connection Specified Condition
    RELIEF VLV relay (1) or DSVR (A53-3) - Body ground 10 kΩ or higher
    RELIEF VLV relay (3) or FRI (E82-1) -Body ground 10 kΩ or higher
    Fig 4: Identifying Relief VLV Relay
    G05813334Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. REPLACE FUEL RELIEF VALVE 
  10. PERFORM ACTIVE TEST USING TECHSTREAM (FP REL VLV) 
    1. Put the engine in inspection mode (See INSPECTION MODE PROCEDURE ).
    2. Warm up the engine.
    3. Connect the Techstream to the DLC3.
    4. Turn the Techstream on.
    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press and Coolant Temp and Battery Voltage.
      NOTE:
      • Coolant Temp value is 50°C (122°F) or more
      • Battery Voltage value is 10 V or more
      • Fuel Press value is 2 MPa or more
    6. Turn the power switch off.
    7. Wait for 10 seconds.
    8. Put the engine in inspection mode.
    9. Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
    10. After starting the engine, turn the power switch off within 45 seconds.

      HINT:

      Before turning the power switch off, write down the Fuel Press value.

    11. Wait for 10 seconds. Then turn the power switch on (IG).
    12. Enter the following menus: Powertrain / Engine and ECT / Active Test / Fuel Pressure Relief Valve Open / Fuel Press and Coolant Temp and Battery Voltage.
    13. Before turning the power switch off, check if the Fuel Press value is stable.

      HINT:

      Before performing the Active Test, check that the following conditions are met.

      • Coolant Temp value is 50°C (122°F) or more
      • Battery Voltage value is 10 V or more
      • Fuel Press value is 2 MPa or more
    14. Set Fuel Pressure Relief Valve Open to ON and open the fuel relief valve.
      NOTE:
      • Wait 30 seconds after turning the power switch on (IG). If ON is selected before 30 seconds have passed, the Active Test will not operate.
      • After selecting ON, the Active Test will turn off automatically after 2 seconds have passed.
      • After ON is selected, ON will not be operable for 60 seconds.
    15. After performing the Active Test, check the fuel pressure.

    OK: 

    Fuel pressure decreases 

    NG: REPLACE ECM 

    OK: END 

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