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Home >> Lexus >> 2007 >> GS 450h >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTC P0010 - P0113 >> DTC P0088 Fuel Rail / System Pressure - Too High >> Inspection Procedure
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Inspection Procedure

HINT:

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 (see FREEZE FRAME DATA ).

  1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0088) 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the power switch ON (IG) and turn the tester ON.
    3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
    4. Read the DTCs using the intelligent tester.

      Result 

      RESULT CHART

      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 BY INTELLIGENT TESTER (FP REL VLV) 
    1. Put the engine in inspection mode (see INSPECTION MODE PROCEDURE ).
    2. Warm up the engine.
    3. Connect the intelligent tester to the DLC3.
    4. Turn the tester ON.
    5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / 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: DIAGNOSIS / ENHANCED OBD II / 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: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / FP REL VLV OPN / USER DATA / 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 FP REL VLV OPN 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: Fuel Pressure Graph
      G05302306Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result 

      RESULT CHART

      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 intelligent tester to the DLC3.
    4. Turn the tester ON.
    5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
    6. Read the DTCs using the intelligent tester.

      Result 

      RESULT CHART

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

    B: END 

    A: GO TO Next Step 

  5. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (TARGET FUEL PRESS) 
    1. Put the engine in inspection mode (see INSPECTION MODE PROCEDURE ).
    2. Connect the intelligent tester to the DLC3.
    3. Turn the tester ON.
    4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / TARGET FUEL PRESS / USER DATA/FUEL PRESS.
    5. Check that the fuel pressure fluctuates when the target fuel pressure changes.

      HINT:

      The TARGET FUEL 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.
      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 FUEL RELIEF VALVE RELAY 
    1. Remove the fuel relief valve relay from the engine room No. 1 relay block.
    2. Measure the resistance of the fuel relief valve relay.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      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 EFI Relay
      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 fuel relief valve 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 SPECIFIED CONDITION CHART

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

      Standard resistance (Check for short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      Fuel relief valve relay (1) or DSVR (A53-3) - Body ground 10 kΩ or higher
      Fuel relief valve relay (3) or FRI (E82-1) -Body ground 10 kΩ or higher
      Fig 4: Identifying Fuel Relief Valve Relay
      G05302309Courtesy 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 BY INTELLIGENT TESTER (FP REL VLV) 
    1. Put the engine in inspection mode (see INSPECTION MODE PROCEDURE ).
    2. Warm up the engine.
    3. Connect the intelligent tester to the DLC3.
    4. Turn the tester ON.
    5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / 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: DIAGNOSIS / ENHANCED OBD II / 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: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / FP REL VLV OPN / USER DATA /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 FP REL VLV OPN 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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