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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 119 (Engine Control System - Diagnostic Codes (08 Of 10)) >> SFI SYSTEM (for Gasoline Model) >> DTC P12D4-1D: Fuel Pump Control Circuit Current Out of Range [10/2022 - ] >> Procedure

DTC P12D4-1D: Fuel Pump Control Circuit Current Out of Range [10/2022 - ]: Procedure

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  1. INSPECT FUEL PUMP CONTROL ECU 

    Pre-procedure1

    • Measure the resistance according to the value(s) in the table below.
      GTY1131346Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Fuel Pump Control ECU)
      - -

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H121-2 (FPU) - H122-3 (GND) Always 2 kΩ or higher
      H121-3 (FPV) - H122-3 (GND) Always 2 kΩ or higher
      H121-4 (FPW) - H122-3 (GND) Always 2 kΩ or higher

      HINT: 

      This procedure checks for an internal short of the fuel pump control ECU when its transistor is stuck on.

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    NG 

    REPLACE FUEL PUMP CONTROL ECU. Refer to  REMOVAL [10/2022 - ] 

    Result: 

    OK 

    See step  2

  2. PERFORM ACTIVE TEST USING GTS (FUEL PUMP SINGLE PHASE ENERGIZATION) 

    Pre-procedure1

    • Disconnect the H121 fuel pump control ECU connector.
    • Operate the fuel pump control ECU using the Active Test function and measure the voltage according to the value(s) in the table below.
      GTY1133655Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Fuel Pump Control ECU)

      Powertrain > Engine > Active Test 

      Tester Display
      Fuel Pump Single Phase Energization

      Standard Voltage

      Tester Connection GTS Operation Specified Condition
      H121-2 (FPU) - Body ground U Phase 4.4 to 8.4 V*
      H121-3 (FPV) - Body ground 8 to 15.5 V
      H121-4 (FPW) - Body ground 8 to 15.5 V
      H121-3 (FPV) - Body ground V Phase 4.4 to 8.4 V*
      H121-2 (FPU) - Body ground 8 to 15.5 V
      H121-4 (FPW) - Body ground 8 to 15.5 V
      H121-4 (FPW) - Body ground W Phase 4.4 to 8.4 V*
      H121-2 (FPU) - Body ground 8 to 15.5 V
      H121-3 (FPV) - Body ground 8 to 15.5 V

      HINT: 

      • *: This Active Test limits the fuel pump control ECU output duty cycle to 50%. Therefore, the output voltage of the fuel pump control ECU will be approximately 50% of the power source voltage (+B terminal).
      • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    NG 

    REPLACE FUEL PUMP CONTROL ECU. Refer to  REMOVAL [10/2022 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU - FUEL PUMP (FOR LOW PRESSURE SIDE)) 

    Pre-procedure1

    • Disconnect the fuel pump control ECU connector.
    • Disconnect the fuel pump (for low pressure side) connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H121-2 (FPU) or H187-3 (BLPU) - Other terminals Always 10 kΩ or higher
      H121-3 (FPV) or H187-4 (BLPV) - Other terminals Always 10 kΩ or higher
      H121-4 (FPW) or H187-2 (BLPW) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 

    HINT: 

    Refer to REMOVAL [10/2022 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  5

  5. CLEAR DTC 

    Pre-procedure1

    • None.
    • Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

      Result

      Proceed to
      NEXT

    Post-procedure1

    • Turn the ignition switch off and wait for at least 30 seconds.

    Result: 

    NEXT 

    See step  6

  6. CHECK WHETHER DTC OUTPUT RECURS (DTC P12D4-1D) 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      OK

      DTCs are not output.

      Result

      Proceed to
      NEXT

    Post-procedure1

    • None.

    Result: 

    NEXT 

    END