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Home >> Lexus >> 2019 >> LX 570 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (7 Of 7) & Circuit Tests >> SFI System >> Fuel Pump Control Circuit [08/2018 - ] >> Procedure
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Fuel Pump Control Circuit [08/2018 - ]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE FUEL PUMP / SPEED) 
    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 / Active Test / Control the Fuel Pump / Speed.
    5. Check whether operating sounds can be heard while operating the relay using the Techstream.

      OK

      Operating sounds can be heard from fuel pump.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  2

  2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE FUEL PUMP DUTY) 
    1. Remove the fuel pump from the fuel tank assembly.

      Refer to REMOVAL [08/2016 - ]

    2. Clean the fuel pump to completely remove any remaining fuel.
    3. Connect the fuel pump connector.
      WARNING:

      Confirm that no fuel remains inside or on the outside of the fuel pump.

    4. Connect the Techstream to the DLC3.
    5. Turn the engine switch on (IG).
    6. Turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine / Active Test / Control the Fuel Pump Duty.
    8. Operate the fuel pump using the active test function and measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Techstream Operation Specified Condition
      1 - 2 FPC Duty: 25% 3.2 to 4.05 V
      FPC Duty: 80% 8.8 to 12.5 V
    9. Enter the following menus: Powertrain / Engine / Active Test / Control the Fuel Pump / Speed.
    10. Operate the fuel pump using the active test function and measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Techstream Operation Specified Condition
      1 - 2 ON (FPC Duty: 90%) 9.0 to 14.0 V

      HINT: 

      • Be sure to measure the voltage with all of the connectors connected.
      • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. INSPECT FUEL PUMP 
    1. Inspect the fuel pump.

      Refer to INSPECTION [09/2015 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the fuel pump.

      Refer to INITIALIZATION [09/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    See step  4

  4. REPLACE FUEL PUMP 
    1. Replace the fuel pump.

      Refer to REMOVAL [08/2016 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the fuel pump.

      Refer to INITIALIZATION [09/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

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

      OK

      Malfunction has been repaired successfully.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [09/2015 - ] 

  6. CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL PUMP CONTROL ECU ASSEMBLY) 
    1. Disconnect the fuel pump ECU connector.
      GTY788151Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fuel pump ECU)
    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
      N12-6 (+B) - N12-3 (E) Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  7

  7. INSPECT FUEL PUMP 
    1. Inspect the fuel pump.

      Refer to INSPECTION [09/2015 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the fuel pump.

      Refer to INITIALIZATION [09/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FUEL PUMP. Refer to  REMOVAL [08/2016 - ] 

    Result: 

    OK 

    See step  8

  8. 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 Switch Condition Specified Condition
      N1-4 (B2) - N12-1 (FP) Always Below 1 Ω
      N1-5 (E2) - N12-2 (FP-) Always Below 1 Ω
      N1-4 (B2) or N12-1 (FP) - Body ground Always 10 kΩ or higher
      N1-5 (E2) or N12-2 (FP-) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - ECM AND BODY GROUND) 
    1. Disconnect the ECM 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 Switch Condition Specified Condition
      A38-50 (FPC) - N12-5 (FPC) Always Below 1 Ω
      N12-3 (E) - Body ground Always Below 1 Ω
      A38-50 (FPC) or N12-5 (FPC) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. INSPECT ECM (FPC TERMINAL) 
    1. Disconnect the fuel pump ECU connector.
      GTY788161Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fuel pump ECU)
    2. Connect the Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Powertrain / Engine / Active Test / Control the Fuel Pump / Speed.
    6. Operate the fuel pump ECU using the Active Test function and measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      N12-5 (FPC) - Body ground Before Active Test → During Active Test Before Active Test: Resistance is stable → During Active Test: Resistance fluctuates*

      HINT: 

      *: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the FPC terminal will be unstable during the Active Test. If the resistance is stable before the Active Test and fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUEL PUMP ECU. Refer to  REMOVAL [09/2015 - ] 

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [09/2015 - ] 

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

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      N12-3 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

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

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      1P-6 - N12-6 (+B) Always Below 1 Ω
      1P-7 - Body ground Always Below 1 Ω
      1P-6 or N12-6 (+B) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. INSPECT INTEGRATION RELAY (FUEL PMP) 
    1. Inspect the integration relay (FUEL PMP).

      Refer to PROCEDURE - Step 2

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO ECM POWER SOURCE CIRCUIT. Refer to  ECM Power Source Circuit [09/2015 - ]  

    Result: 

    NG 

    REPLACE INTEGRATION RELAY 

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