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Home >> Lexus >> 2018 >> NX 300 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Circuit Tests & Symptom Tests (2 Of 2) >> SFI System >> Fuel Pump Control Circuit [10/2014 - 09/2017] >> Procedure
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Fuel Pump Control Circuit [10/2014 - 09/2017]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE CIRCUIT RELAY) 
    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 / Activate the Circuit Relay.

      Powertrain > Engine > Active Test 

      Tester Display
      Activate the Circuit Relay
    5. Check whether the fuel pump operating sound occurs when performing the Active Test on the Techstream.

      OK

      Operating sounds can be heard from fuel pump (for low pressure side).

      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 RATIO, ACTIVATE THE CIRCUIT RELAY) 
    1. Remove the fuel suction with pump and gauge tube assembly.
    2. Clean the fuel suction with pump and gauge tube assembly to completely remove any remaining fuel.
    3. Remove the fuel pump (for low pressure side).
    4. Connect the fuel pump and fuel suction with pump and gauge tube assembly connector.
      NOTE:

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

    5. Connect the Techstream to the DLC3.
    6. Turn the engine switch on (IG).
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine / Active Test / Control the Fuel Pump Duty Ratio.

      Powertrain > Engine > Active Test 

      Tester Display
      Control the Fuel Pump Duty Ratio
    9. 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 Fuel pump control duty: 25% 3.2 to 4.05 V
      Fuel pump control duty: 80% 8.8 to 12.5 V
      GTY502738Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Fuel Pump (for low pressure side))
    10. Enter the following menus: Powertrain / Engine / Active Test / Activate the Circuit Relay.

      Powertrain > Engine > Active Test 

      Tester Display
      Control the Fuel Pump Duty Ratio
    11. 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 (Fuel pump control duty: 90%) 9.0 to 14.0 V

      HINT: 

      • Be sure to measure the voltage with all 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  8

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - ECM) 
    1. Disconnect the fuel pump control ECU assembly 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
      Q14-2 (FPC) - A35-21 (FPC) Always Below 1 Ω
      Q14-2 (FPC) or A35-21 (FPC) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 
    1. Replace the fuel pump (for low pressure side).

      Refer to REMOVAL [10/2014 - ]

      HINT: 

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

      Refer to INITIALIZATION [10/2014 - 05/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Check the fuel pump (for low pressure side) operation.

      OK

      Malfunction has been repaired successfully.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [10/2014 - 05/2019] 

  6. CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL PUMP CONTROL ECU ASSEMBLY) 
    1. Disconnect the fuel pump control ECU Assembly connector.
      GTY517521Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fuel Pump Control ECU Assembly)
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      Q14-1 (+B) - Body ground Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  7

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      Q14-4 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (FUEL PUMP (FOR LOW PRESSURE SIDE) - FUEL PUMP CONTROL ECU ASSEMBLY) 
    1. Disconnect the fuel pump control ECU assembly connector.
    2. Disconnect the fuel suction plate sub-assembly (fuel pump (for low pressure side)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      b1-4 (B) - Q14-6 (FP) Always Below 1 Ω
      b1-5 (E) - Q14-5 (FP-) Always Below 1 Ω
      b1-4 (B) or Q14-6 (FP) - Body ground and other terminals Always 10 kΩ or higher
      b1-5 (E) or Q14-5 (FP-) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. INSPECT FUEL PUMP (FOR LOW PRESSURE SIDE) 
    1. Inspect fuel pump (for low pressure side).

      Refer to INSPECTION [10/2014 - ]

      HINT: 

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

      Refer to INITIALIZATION [10/2014 - 05/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 

    (Refer to REMOVAL [10/2014 - ] )

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - ECM) 
    1. Disconnect the fuel pump control ECU assembly 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
      Q14-2 (FPC) - A35-21 (FPC) Always Below 1 Ω
      Q14-2 (FPC) or A35-21 (FPC) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. REPLACE FUEL PUMP CONTROL ECU ASSEMBLY 
    1. Replace the fuel pump control ECU assembly.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  12

  12. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Check the fuel pump (for low pressure side) operation.

      OK

      Malfunction has been repaired successfully.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [10/2014 - 05/2019] 

  13. INSPECT EFI-MAIN NO. 2 RELAY 
    1. Inspect the EFI-MAIN NO. 2 relay.

      Refer to ON-VEHICLE INSPECTION [10/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE EFI-MAIN NO. 2 RELAY 

    Result: 

    OK 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF EFI-MAIN NO. 2 RELAY) 
    1. Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and junction block assembly.
      GTY505067Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI-MAIN NO. 2 Relay
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      5 (EFI-MAIN NO. 2 relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - EFI-MAIN NO. 1, FUEL PUMP CONTROL ECU ASSEMBLY, BODY GROUND) 
    1. Remove the EFI-MAIN NO. 1 relay and EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and junction block assembly.
    2. Disconnect the fuel pump control ECU assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (EFI-MAIN NO. 2 relay) - Q14-1 (+B) Always Below 1 Ω
      3 (EFI-MAIN NO. 1 relay) - 1 (EFI-MAIN NO. 2 relay) Always Below 1 Ω
      2 (EFI-MAIN NO. 2 relay) - Body ground Always Below 1 Ω
      3 (EFI-MAIN NO. 2 relay) or Q14-1 (+B) - Body ground and other terminals Always 10 kΩ or higher
      3 (EFI-MAIN NO. 1 relay) or 1 (EFI-MAIN NO. 2 relay) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO ECM POWER SOURCE CIRCUIT. Refer to  ECM Power Source Circuit [10/2014 - ]  

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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