LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2018 >> RX 350 Base, FWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System - Diagnostics - Circuit Tests >> SFI System >> Circuit Tests >> Fuel Pump Control Circuit [09/2015 - 12/2017] >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Fuel Pump Control Circuit [09/2015 - 12/2017]: 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 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

      Standard

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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

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

      Refer to PROCEDURE - Step 2

    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 Duty Ratio / Data List / Fuel Pressure (Low) / Fuel Pressure 2.

      Powertrain > Engine > Active Test 

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

      Standard

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

      HINT: 

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

      Refer to INITIALIZATION [09/2015 - 08/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FUEL DELIVERY PIPE SUB-ASSEMBLY (FUEL PRESSURE SENSOR (FOR LOW PRESSURE SIDE)). Refer to  REMOVAL [09/2015 - 08/2016]  , or refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM (FUEL PRESSURE) 
    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 / Data List / Target Fuel Pressure (Low) / Target Fuel Pressure 2, Fuel Pressure (Low) / Fuel Pressure 2 and Low Fuel Pressure Sensor.

      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: 

    B 

    REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 

    HINT: 

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

    Result: 

    C 

    See step  6

    Result: 

    A 

    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 10 [09/2015 - 08/2016] , or refer to PROCEDURE - Step 10 [08/2016 - 08/2019]

    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 psi) or more

      HINT: 

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

      Refer to INITIALIZATION [09/2015 - 08/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [09/2015 - 12/2017]

    HINT: 

    If the difference between Target Fuel Pressure (Low) / Target Fuel Pressure 2 and Low Fuel Pressure Sensor is more than 200 kPa in the freeze frame data of DTC (P0087-00, P0190-2A, P107A-2A) and the malfunctioning part could not be identified, replace the fuel pump (for low pressure side) as the fuel supply system, which cannot reproduce symptoms easily, may be malfunctioning.

    Result: 

    NG 

    REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 

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

        Refer to INITIALIZATION [09/2015 - 08/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 

  7. PERFORM ACTIVE TEST USING TECHSTREAM (FUEL PUMP SINGLE PHASE ENERGIZATION) 
    GTY948155Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Fuel Pump (for low pressure side))
    1. Disconnect the fuel pump (for low pressure side) connector.
    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 / Fuel Pump Single Phase Energization.

      Powertrain > Engine > Active Test 

      Tester Display
      Fuel Pump Single Phase Energization
    6. Operate the fuel pump control ECU assembly using the Active Test function and measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection GTS Operation Specified Condition
      S11-3 (BLPU) - Body ground U Phase 4.4 to 8.4 V*
      S11-4 (BLPV) - Body ground V Phase 4.4 to 8.4 V*
      S11-2 (BLPW) - Body ground W Phase 4.4 to 8.4 V*

      HINT: 

      • *: This Active Test restricts the fuel pump control ECU assembly output duty cycle to 50%. Therefore, the output voltage of the fuel pump control ECU assembly 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 (for low pressure side).

        Refer to INITIALIZATION [09/2015 - 08/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) 

    Result: 

    NG 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - FUEL PUMP (FOR LOW PRESSURE SIDE)) 
    1. Disconnect the fuel pump control ECU assembly connector.
    2. Disconnect the 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
      S48-2 (FPU) - S11-3 (BLPU) Always Below 1 Ω
      S48-3 (FPV) - S11-4 (BLPV) Always Below 1 Ω
      S48-4 (FPW) - S11-2 (BLPW) Always Below 1 Ω
      S48-2 (FPU) or S11-3 (BLPU) - Body ground and other terminals Always 10 kΩ or higher
      S48-3 (FPV) or S11-4 (BLPV) - Body ground and other terminals Always 10 kΩ or higher
      S48-4 (FPW) or S11-2 (BLPW) - 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. CHECK HARNESS AND CONNECTOR (POWER SOURCE OF FUEL PUMP CONTROL ECU ASSEMBLY) 
    GTY652485Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Fuel Pump Control ECU Assembly)
    1. Disconnect the fuel pump control ECU assembly connector.
    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
      S49-1 (+B) - S49-3 (GND) Engine switch on (IG) 11 to 14 V

      HINT: 

      Make a note of the measured voltage as it may be used in a following Active Test.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  10

  10. INSPECT ECM (FPC TERMINAL) 
    GTY681314Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Fuel Pump Control ECU Assembly)
    1. Disconnect the fuel pump control ECU assembly connector.
    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 / Fuel Pump Single Phase Energization.

      Powertrain > Engine > Active Test 

      Tester Display
      Fuel Pump Single Phase Energization
    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 Techstream Operation Specified Condition
      S49-2 (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 [09/2015 - ] 

    Result: 

    NG 

    See step  11

  11. 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
      S49-2 (FPC) - A37-18 (FPC) Always Below 1 Ω
      S49-2 (FPC) or A37-18 (FPC) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [09/2015 - 08/2016]  , or refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  12. 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
      S49-3 (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 FUEL PMP RELAY) 
    1. Remove the FUEL PMP relay from the 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
      5 (FUEL PMP relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - FUEL PMP RELAY) 

    Result: 

    OK 

    See step  14

  14. INSPECT FUEL PMP RELAY 
    1. Inspect the FUEL PMP relay.

      Refer to ON-VEHICLE INSPECTION [09/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FUEL PMP RELAY 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - ECM) 
    1. Disconnect the semiconductor PWR integration 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
      1G-6 - A37-46 (MREL) Always Below 1 Ω
      1G-6 or A37-46 (MREL) - 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 (SEMICONDUCTOR PWR INTEGRATION ECU - FUEL PMP RELAY) 
    1. Remove the FUEL PMP relay from the engine room relay block and junction block assembly.
    2. Disconnect the semiconductor PWR integration ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1G-8 - 1 (FUEL PMP relay) Always Below 1 Ω
      1G-8 or 1 (FUEL PMP 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  17

  17. CHECK HARNESS AND CONNECTOR (FUEL PMP RELAY - BODY GROUND) 
    1. Remove the FUEL PMP relay from the 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
      2 (FUEL PMP relay) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  18

  18. CHECK HARNESS AND CONNECTOR (FUEL PMP RELAY - FUEL PUMP CONTROL ECU ASSEMBLY) 
    1. Remove the FUEL PMP relay from the 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 (FUEL PMP relay) - S49-1 (+B) Always Below 1 Ω
      3 (FUEL PMP relay) or S49-1 (+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 [09/2015 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

scientia non olet · About LEMON Manuals