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Home >> Lexus >> 2024 >> LC 500 2D Convertible >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (Convertible) (2 Of 7) >> SFI System >> DTC P0191: Fuel Rail Pressure Sensor Circuit Range / Performance [07/2020 - ] >> Procedure
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DTC P0191: Fuel Rail Pressure Sensor Circuit Range / Performance [07/2020 - ]: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0191) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes 

    5. Read the DTCs.

      Result

      Result Proceed to
      DTC P0191 is output A
      DTC P0191 and P0087, P0088, P0171, P0172, P0174 and/or P0175 are output
      DTC P0191 and other DTCs are output B

      HINT: 

      • If DTC P0191 and P0087, P0088, P0171, P0172, P0174 and/or P0175 are output simultaneously, troubleshoot for DTC P0191 first.
      • If any DTCs other than P0191 are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [07/2020 - 05/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [05/2023 - ] 

    Result: 

    A 

    See step  2

  2. CHECK FUEL LEAK 
    1. Check around and beneath the vehicle for fuel leaks, fumes, etc.

      OK

      No fuel leaks present.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  3

  3. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE TARGET FUEL PRESSURE) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine and warm it up.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Active Test / Control the Target Fuel Pressure / Fuel System / High Fuel Pressure Sensor.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Target Fuel Pressure
      Data List Display
      High Fuel Pressure Sensor
    5. Check the value of the Data List item "High Fuel Pressure Sensor" when the target fuel pressure is increased and decreased using the Active Test.

      Result

      Result Proceed to
      "High Fuel Pressure Sensor" value follows the change in target fuel pressure A
      "High Fuel Pressure Sensor" value does not follow the change in target fuel pressure B

    Result: 

    B 

    See step  10

    Result: 

    A 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (ECM - FUEL DELIVERY PIPE LH (FUEL PRESSURE SENSOR)) 
    1. Disconnect the ECM connector.
    2. Disconnect the fuel delivery pipe LH (fuel pressure sensor) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G42-96 (PR) - J5-3 (PR) Always Below 1 Ω
      G42-127 (EPR) - J5-2 (E2) Always Below 1 Ω
      G42-96 (PR) or J5-3 (PR) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  5

  5. REPLACE FUEL DELIVERY PIPE LH (FUEL PRESSURE SENSOR) 
    1. Replace the fuel delivery pipe LH (fuel pressure sensor).

      Refer to REMOVAL [07/2020 - 05/2023] , or refer to REMOVAL [05/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    5. Turn the engine switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P0191) 
    1. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    2. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes 

    3. Read the pending DTCs.

      Result

      Result Proceed to
      DTC P0191 is output A
      DTCs are not output B

    Result: 

    B 

    END 

    Result: 

    A 

    See step  8

  8. REPLACE ECM 
    1. Replace the ECM.

      Refer to REMOVAL [07/2020 - 05/2023] , or refer to REMOVAL [05/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  12

  9. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace the harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  12

  10. REPLACE FUEL DELIVERY PIPE LH (FUEL PRESSURE SENSOR) 
    1. Replace the fuel delivery pipe LH (fuel pressure sensor).

      Refer to REMOVAL [07/2020 - 05/2023] , or refer to REMOVAL [05/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  12

  11. REPAIR OR REPLACE FUEL LEAK POINT 
    1. Repair or replace the fuel leak point.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  12

  12. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    5. Turn the engine switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  13

  13. CHECK WHETHER DTC OUTPUT RECURS (DTC P0191) 
    1. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    2. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes 

    3. Read the pending DTCs.

      OK

      DTCs are not output

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

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