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Home >> Lexus >> 2021 >> NX 300h Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (6 Of 6) & Circuit Tests >> 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 (CONTROL THE FUEL PUMP / SPEED) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.

      Powertrain > Engine and ECT > Active Test 

      Tester Display
      Control the Fuel Pump / Speed
    5. Check whether the fuel pump operating sounds occurs when performing the Active Test on the Techstream.

      Result

      Result Proceed to
      Fuel pump operating sound occurs A
      Fuel pump operating sound does not occur B

    Result: 

    B 

    See step  6

    Result: 

    A 

    See step  2

  2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE FUEL PUMP DUTY) 
    1. Remove the fuel suction tube assembly.

      Refer to REMOVAL [10/2014 - ]

    2. Clean the fuel suction tube assembly to completely remove any remaining fuel.
    3. Remove the fuel pump.

      Refer to DISASSEMBLY [10/2014 - ]

    4. Connect the fuel pump and fuel suction tube assembly connectors.
      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 power switch on (IG).
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump Duty.

      Powertrain > Engine and ECT > Active Test 

      Tester Display
      Control the Fuel Pump Duty
    9. Operate the fuel pump using the Active Test 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
      GTY379054Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Fuel Pump)
    10. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.

      Powertrain > Engine and ECT > Active Test 

      Tester Display
      Control the Fuel Pump / Speed
    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 auxiliary 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 [10/2014 - ]

      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 [10/2014 - ]

      HINT: 

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

      Refer to INITIALIZATION [10/2014 - ]

      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 [10/2014 - ] 

  6. CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL PUMP CONTROL ECU ASSEMBLY) 
    1. Disconnect the fuel pump control ECU Assembly connector.
      GTY497638Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fuel Pump Control ECU Assembly)
    2. Turn the power 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) - Q14-4 (E) Power 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 [10/2014 - ]

      HINT: 

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

      Refer to INITIALIZATION [10/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FUEL PUMP. Refer to  REMOVAL [10/2014 - ] 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (FUEL PUMP - FUEL PUMP CONTROL ECU ASSEMBLY) 
    1. Disconnect the fuel pump control ECU assembly connector.
    2. Disconnect the fuel pump 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 Always 10 kΩ or higher
      b1-5 (E) or Q14-5 (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 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 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 control ECU assembly connector.
      GTY619912Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fuel Pump Control ECU Assembly)
    2. Connect the Techstream to the DLC3.
    3. Turn the power switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.

      Powertrain > Engine and ECT > Active Test 

      Tester Display
      Control the Fuel Pump / Speed
    6. Operate the fuel pump control ECU assembly using the Active Test function and measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection GTS Operation Specified Condition
      Q14-2 (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 CONTROL ECU ASSEMBLY. Refer to  REMOVAL [10/2014 - ] 

    Result: 

    NG 

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

  11. 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  12

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

      Refer to PROCEDURE - Step 3

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE EFI-MAIN NO. 2 RELAY 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - FUEL PUMP CONTROL ECU ASSEMBLY, AUXILIARY BATTERY) 
    GTY518768Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and Junction Block Assembly
    *2 EFI-MAIN Relay
    *3 EFI-MAIN NO. 2 Relay
    1. Remove the EFI-MAIN relay from the No. 1 engine room relay block and junction block assembly.
    2. Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and junction block assembly.
    3. Disconnect the fuel pump control ECU assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (EFI-MAIN NO. 2 relay) - 3 (EFI-MAIN relay) Always Below 1 Ω
      2 (EFI-MAIN NO. 2 relay) - Body ground Always Below 1 Ω
      3 (EFI-MAIN NO. 2 relay) - Q14-1 (+B) Always Below 1 Ω
      1 (EFI-MAIN NO. 2 relay) or 3 (EFI-MAIN relay) - Body ground Always 10 kΩ or higher
      3 (EFI-MAIN NO. 2 relay) or Q14-1 (+B) - Body ground Always 10 kΩ or higher
    5. 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: 

    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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