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Home >> Lexus >> 2024 >> LX 600 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (W/O Canister Pump Module) - Circuit Tests (2 Of 2) & Symptom Tests >> SFI SYSTEM (w/o Canister Pump Module) >> Fuel Pump Control Circuit [12/2021 - ] >> Procedure
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Fuel Pump Control Circuit [12/2021 - ]: Procedure

  1. CHECK FUEL LEAK 
    1. Check around and beneath the vehicle for fuel leaks, fumes, etc.

      OK

      No fuel leaks present.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE FUEL LEAK POINT 

    Result: 

    OK 

    See step  2

  2. PERFORM ACTIVE TEST USING GTS (ACTIVATE THE CIRCUIT RELAY (BRUSHLESS)) 
    1. Check whether the fuel pump operating sound occurs when performing the Active Test on the GTS.

      Powertrain > Engine > Active Test 

      Tester Display
      Activate the Circuit Relay (Brushless)

      Standard

      GTS Operation Standard
      ON Operating sounds can be heard from fuel pump assembly (for low pressure side)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. PERFORM ACTIVE TEST USING GTS (CONTROL THE FUEL PUMP DUTY RATIO (BRUSHLESS)) 
    1. Install the fuel pressure gauge (for low pressure line of low pressure side).

      Refer to PROCEDURE - Step 2

    2. Compare the values in the Data List using the GTS and the fuel pressure gauge when the Active Test was performed.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Fuel Pump Duty Ratio (Brushless)
      Data List Display
      Fuel Pressure (Low) / Fuel Pressure 2
      Fuel Pump Control Duty Ratio

      Standard

      GTS Operation Standard
      Low Data List value and fuel pressure gauge are within +/-50 kPa of each other
      High

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FUEL PRESSURE SENSOR (FOR LOW PRESSURE SIDE). Refer to  REMOVAL [12/2021 - ] 

    Result: 

    OK 

    See step  4

  4. READ VALUE USING GTS (FUEL PRESSURE) 
    1. Read the values displayed on the GTS while the engine is cranking.

      Powertrain > Engine > Data List 

      Tester Display
      Target Fuel Pressure (Low) / Target Fuel Pressure 2
      Fuel Pressure (Low) / Fuel Pressure 2
      Low Fuel Pressure Sensor

      Result

      Result Proceed to
      Low Fuel Pressure Sensor value is within +/- 65 kPag of the Target Fuel Pressure (Low) / Target Fuel Pressure 2 A
      Low Fuel Pressure Sensor value is more than 65 kPag higher than the target fuel pressure (low) / Target Fuel Pressure 2 B
      Low Fuel Pressure Sensor value is more than 65 kPag lower than the target fuel pressure (low) / Target Fuel Pressure 2 C

    Result: 

    REPLACE FUEL PUMP ASSEMBLY (FOR LOW PRESSURE SIDE) (FUEL WITH FILTER PUMP ASSEMBLY) 

    for Single Tank Type: Refer to REMOVAL [12/2021 - ]

    for Double Tank Type: Refer to REMOVAL [12/2021 - ]

    HINT: 

    Relief blockage such as clogging of the jet pump is suspected.

    Result: 

    See step  6

    Result: 

    See step  5

  5. CHECK FUEL PRESSURE 
    1. Install the fuel pressure gauge (for low pressure line of low pressure side).

      Refer to PROCEDURE - Step 2

    2. Start the engine.
    3. Measure the fuel pressure at idle.

      Standard Fuel Pressure

      196 to 833 kPa (2.0 to 8.5 kgf/cm2 , 28 to 121 psi)

      HINT: 

      Refer to Standard Idle Speed.

      Refer to PROCEDURE - Step 12

    4. Stop the engine.
    5. Check that the fuel pressure remains as specified for 5 minutes.

      Standard Fuel Pressure

      98 kPa (1.0 kgf/cm2 , 14.2 psi) or more

      HINT: 

      Perform "Inspection After Repair" after replacing the fuel pump assembly (for low pressure side).

      Refer to INITIALIZATION [12/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [12/2021 - ] 

    Result: 

    NG 

    REPLACE FUEL PUMP ASSEMBLY (FOR LOW PRESSURE SIDE) (FUEL WITH FILTER PUMP ASSEMBLY) 

    for Single Tank Type: Refer to REMOVAL [12/2021 - ]

    for Double Tank Type: Refer to REMOVAL [12/2021 - ]

  6. CHECK SHORTAGE OF FUEL 
    1. Check the amount of fuel remaining.

      HINT: 

      • No fuel remains in the fuel tank: Malfunction of the fuel sender gauge assembly is suspected.
      • Only the fuel pump side fuel chamber has no fuel remaining: Malfunction of the jet pump is suspected.
      • Fuel remains in the fuel tank: Malfunction of the fuel pump assembly (for low pressure side) is suspected.
      • Perform "Inspection After Repair" after replacing the fuel pump assembly (for low pressure side).

        Refer to INITIALIZATION [12/2021 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    REPLACE FUEL PUMP ASSEMBLY (FOR LOW PRESSURE SIDE) (FUEL WITH FILTER PUMP ASSEMBLY) 

    for Single Tank Type: Refer to REMOVAL [12/2021 - ]

    for Double Tank Type: Refer to REMOVAL [12/2021 - ]

  7. PERFORM ACTIVE TEST USING GTS (FUEL PUMP SINGLE PHASE ENERGIZATION) 
    1. Disconnect the fuel pump assembly (for low pressure side) connector.
    2. Operate the fuel pump control ECU using the Active Test function and measure the voltage according to the value(s) in the table below.

      Powertrain > Engine > Active Test 

      Tester Display
      Fuel Pump Single Phase Energization

      Standard Voltage

      Tester Connection GTS Operation Specified Condition
      V9-3 (BLPU) - Body ground U Phase 4.4 to 8.4 V*
      V9-4 (BLPV) - Body ground V Phase 4.4 to 8.4 V*
      V9-2 (BLPW) - Body ground W Phase 4.4 to 8.4 V*

      HINT: 

      • *: This Active Test restricts 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.
      • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).
      • Perform "Inspection After Repair" after replacing the fuel pump assembly (for low pressure side).

        Refer to INITIALIZATION [12/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUEL PUMP ASSEMBLY (FOR LOW PRESSURE SIDE) (FUEL WITH FILTER PUMP ASSEMBLY) 

    for Single Tank Type: Refer to REMOVAL [12/2021 - ]

    for Double Tank Type: Refer to REMOVAL [12/2021 - ]

    Result: 

    NG 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU - FUEL PUMP ASSEMBLY (FOR LOW PRESSURE SIDE)) 
    1. Disconnect the fuel pump control ECU connector.
    2. Disconnect the fuel pump assembly (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
      V7-2 (FPU) - V9-3 (BLPU) Always Below 1 Ω
      V7-3 (FPV) - V9-4 (BLPV) Always Below 1 Ω
      V7-4 (FPW) - V9-2 (BLPW) Always Below 1 Ω
      V7-2 (FPU) or V9-3 (BLPU) - Body ground and other terminals Always 10 kΩ or higher
      V7-3 (FPV) or V9-4 (BLPV) - Body ground and other terminals Always 10 kΩ or higher
      V7-4 (FPW) or V9-2 (BLPW) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      HINT: 

      Perform "Inspection After Repair" after replacing the fuel pump assembly (for low pressure side).

      Refer to INITIALIZATION [12/2021 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (POWER SOURCE OF FUEL PUMP CONTROL ECU) 
    1. Disconnect the fuel pump control ECU connector.
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      V6-1 (+B) - V6-3 (GND) Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  10

  10. INSPECT ECM (FPC TERMINAL) 
    1. Disconnect the fuel pump control ECU connector.
    2. Operate the fuel pump control ECU using the Active Test function and measure the resistance according to the value(s) in the table below.

      Powertrain > Engine > Active Test 

      Tester Display
      Fuel Pump Single Phase Energization

      Standard Resistance

      Tester Connection GTS Operation Specified Condition
      V6-2 (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. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU - ECM) 
    1. Disconnect the fuel pump control 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
      V6-2 (FPC) - B70-4 (FPC) Always Below 1 Ω
      V6-2 (FPC) or B70-4 (FPC) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      V6-3 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF EFI MAIN NO. 2 RELAY) 
    GTY1074156Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 2 Engine Room Relay Block and Junction Block Assembly
    *2 EFI MAIN NO. 2 Relay
    1. Remove the EFI MAIN NO. 2 relay from the No. 2 engine room relay block and junction block assembly.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      3 (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 (BATTERY - EFI MAIN NO. 2 RELAY) 

    Result: 

    OK 

    See step  14

  14. INSPECT EFI MAIN NO. 2 RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE EFI MAIN NO. 2 RELAY 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (EFI MAIN NO. 1 - EFI MAIN NO. 2 RELAY) 
    1. Remove the EFI MAIN NO. 1 and EFI MAIN NO. 2 relay from the No. 2 engine room relay block and junction block assembly.
    2. Remove the IGT/INJ relay, A/F relay and EFI MAIN NO. 3 relay from the No. 2 engine room relay block and junction block assembly.

      HINT: 

      Remove the IGT/INJ relay, A/F relay and EFI MAIN NO. 3 relay connected between the checked terminals as the coil inside the relay influences the measurement value.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (EFI MAIN NO. 1 relay) - 2 (EFI MAIN NO. 2 relay) Always Below 1 Ω
      5 (EFI MAIN NO. 1 relay) or 2 (EFI MAIN NO. 2 relay) - 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  16

  16. CHECK HARNESS AND CONNECTOR (EFI MAIN NO. 2 RELAY - BODY GROUND) 
    1. Remove the EFI MAIN NO. 2 relay from the No. 2 engine room relay block and junction block assembly.
    2. 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) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  17

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (EFI MAIN NO. 2 relay) - V6-1 (+B) Always Below 1 Ω
      5 (EFI MAIN NO. 2 relay) or V6-1 (+B) - 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 [12/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR