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Home >> Lexus >> 2021 >> GX 460 Base >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (Circuit Tests) (2 Of 2) >> SFI System >> Fuel Pump Control Circuit [08/2015 - 08/2019] >> Procedure
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Fuel Pump Control Circuit [08/2015 - 08/2019]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (FUEL PUMP) 
    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 and ECT / Active Test / Control the Fuel Pump / Speed.
    5. Check whether operating sounds can be heard while operating the fuel pump using the Techstream.

      OK

      Operating sounds can be heard from fuel pump.

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    (Refer to PROBLEM SYMPTOMS TABLE [08/2015 - 08/2019] )

    Result: 

    NG 

    See step  2

  2. INSPECT CIRCUIT OPENING RELAY (C/OPN) 
    1. Inspect the circuit opening relay (C/OPN) (Refer to PROCEDURE - Step 1 ).

    Result: 

    NG 

    REPLACE CIRCUIT OPENING RELAY (C/OPN) 

    Result: 

    OK 

    See step  3

  3. INSPECT CIRCUIT OPENING RELAY (C/OPN) (POWER SOURCE VOLTAGE) 
    GTY264296Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the circuit opening relay (C/OPN) from the engine room relay block.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      C/OPN relay (2) - Body ground Engine switch on (IG) 11 to 14 V
      C/OPN relay (5) - Body ground Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block
      *2 Circuit Opening Relay (C/OPN)

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (C/OPN) - ECM AND FUEL PUMP ECU) 
    1. Remove the circuit opening relay (C/OPN) from the engine room relay block.
    2. Disconnect the ECM connector.
    3. Disconnect the fuel pump ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C/OPN relay (1) - G45-8 (FC) Always Below 1 Ω
      C/OPN relay (3) - S7-4 (+B) Always Below 1 Ω
      C/OPN relay (1) or G45-8 (FC) - Body ground Always 10 kΩ or higher
      C/OPN relay (3) or S7-4 (+B) - Body ground Always 10 kΩ or higher

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (FUEL PUMP - FUEL PUMP ECU) 
    1. Disconnect the fuel pump connector.
    2. Disconnect the fuel pump ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      S4-4 (B2) - S8-1 (FP) Always Below 1 Ω
      S4-5 (E2) - S8-2 (FP-) Always Below 1 Ω
      S4-4 (B2) or S8-1 (FP) - Body ground Always 10 kΩ or higher
      S4-5 (E2) or S8-2 (FP-) - Body ground Always 10 kΩ or higher

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. INSPECT FUEL PUMP 
    1. Inspect the fuel pump (Refer to PROCEDURE - Step 1 ).

      HINT: 

      Perform "Inspection After Repair" after replacing the fuel pump (Refer to INITIALIZATION [08/2015 - ] ).

    Result: 

    NG 

    REPLACE FUEL PUMP 

    (Refer to REMOVAL [08/2015 - ] )

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - ECM AND BODY GROUND) 
    1. Disconnect the fuel pump ECU connector.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      S7-1 (FPC) - G44-3 (FPC) Always Below 1 Ω
      S7-2 (DI) - G45-26 (DI) Always Below 1 Ω
      S7-3 (E) - Body ground Always Below 1 Ω
      S7-1 (FPC) or G44-3 (FPC) - Body ground Always 10 kΩ or higher
      S7-2 (DI) or G45-26 (DI) - Body ground Always 10 kΩ or higher

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. REPLACE FUEL PUMP ECU 
    1. Replace the fuel pump ECU (Refer to REMOVAL [08/2015 - ] ).

    Result: 

    NEXT 

    See step  9

  9. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Check the fuel pump operation.

      OK

      Malfunction has been repaired successfully.

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE ECM 

    (Refer to REMOVAL [08/2015 - ] )

  10. CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (C/OPN) - FUEL PUMP RELAY (FUEL PMP) AND NO. 1 INTEGRATION RELAY) 
    1. Remove the circuit opening relay (C/OPN) from the engine room relay block.
    2. Remove the fuel pump relay (FUEL PMP) from the engine room relay block.
    3. Remove the No. 1 integration relay from the engine room relay block.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C/OPN relay (2) - 1A-5 Always Below 1 Ω
      C/OPN relay (5) - FUEL PMP relay (3) Always Below 1 Ω
      C/OPN relay (2) or 1A-5 - Body ground Always 10 kΩ or higher
      C/OPN relay (5) or FUEL PMP relay (3) - Body ground Always 10 kΩ or higher

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. INSPECT FUEL PUMP RELAY (FUEL PMP) 
    1. Inspect the fuel pump relay (FUEL PMP) (Refer to PROCEDURE - Step 7 ).

    Result: 

    NG 

    REPLACE FUEL PUMP RELAY (FUEL PMP) 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (FUEL PUMP RELAY (FUEL PMP) - NO. 1 INTEGRATION RELAY, BATTERY AND BODY GROUND) 
    1. Disconnect the cable from the negative (-) battery terminal and wait for 1 minute.
    2. Remove the fuel pump relay (FUEL PMP) from the engine room relay block.
    3. Remove the No. 1 integration relay from the engine room relay block.
    4. Disconnect the No. 1 integration relay connector.
    5. Disconnect the cable from the battery positive (+) terminal.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      FUEL PMP relay (1) - 1B-4 Always Below 1 Ω
      FUEL PMP relay (5) - Positive (+) battery cable Always Below 1 Ω
      FUEL PMP relay (2) - Body ground Always Below 1 Ω
      FUEL PMP relay (1) or 1B-4 - Body ground Always 10 kΩ or higher
      FUEL PMP relay (5) or Positive (+) battery cable - Body ground Always 10 kΩ or higher

    Result: 

    OK 

    GO TO ECM POWER SOURCE CIRCUIT 

    (Refer to ECM Power Source Circuit [08/2015 - 08/2019] )

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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