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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 63 (Engine Control System (A25A-FXS) - Diagnostic Codes (P0171-P0190)) >> SFI System >> DTC P0171-00: System Too Lean Bank 1; DTC P0172-00: System Too Rich Bank 1; DTC P1170-00: Fuel Performance/Port Injector; DTC P117B-00: Fuel Performance/Direct Injector [10/2022 - 11/2023] >> Procedure

DTC P0171-00: System Too Lean Bank 1; DTC P0172-00: System Too Rich Bank 1; DTC P1170-00: Fuel Performance/Port Injector; DTC P117B-00: Fuel Performance/Direct Injector [10/2022 - 11/2023]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0171-00, P0172-00, P1170-00 AND/OR P117B-00) 
    1. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTC P0171-00, P0172-00, P1170-00 and/or P117B-00 is output A
      DTC P0171-00, P0172-00, P1170-00 and/or P117B-00 and other DTCs are output B

      HINT: 

      If any DTCs other than P0171-00, P0172-00, P1170-00 and/or P117B-00 are output, troubleshoot those DTCs first.

    Result: 

    GO TO DTC CHART  . Refer to DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 11/2023]

    Result: 

    See step  2

  2. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION MODE) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Port.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Mode
      Data List Display
      Injection Mode
      Short FT B1S1
      Long FT B1S1

      OK

      GTS Display Specified Condition
      Total of Short FT B1S1 and Long FT B1S1 Between -20 and 20%
    4. According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Mode
      Data List Display
      Injection Mode
      Short FT B1S1
      Long FT B1S1

      OK

      GTS Display Specified Condition
      Total of Short FT B1S1 and Long FT B1S1 Between -20 and 20%

      Result

      Item Proceed to
      Port Direct
      OK OK A
      OK NG B
      NG OK C
      NG NG D

    Result: 

    See step  4

    Result: 

    See step  11

    Result: 

    See step  12

    Result: 

    See step  3

  3. CHECK IF VEHICLE HAS RUN OUT OF FUEL IN PAST 
    1. Has the vehicle run out of fuel in the past?

      Result

      Proceed to
      YES
      NO

    Result: 

    YES 

    DTC CAUSED BY RUNNING OUT OF FUEL 

    Result: 

    NO 

    CHECK FOR INTERMITTENT PROBLEMS 

    Refer to CHECK FOR INTERMITTENT PROBLEMS [12/2019 - ]

  4. READ VALUE USING GTS (FUEL PRESSURE (HIGH)) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. According to the display on the GTS, read the Data List.

      Powertrain > Engine > Data List 

      Tester Display
      Engine Speed
      Fuel Pressure (High)
      Injection Mode

      HINT: 

      During charge control, the engine speed is set at idle. Therefore, the engine speed will not increase when the accelerator pedal is depressed. In this case, read the Data List after charge control has completed.

      Standard

      GTS Display Condition Specified Condition
      Fuel Pressure (High)
      • Shift position: P
      • A/C: Off
      • Engine warmed up
      • Engine Speed: 2500 rpm
      • Injection Mode: Direct
      3000 to 25000 kPa

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  5

  5. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION MODE (DIRECT)) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Mode
      Data List Display
      High Pressure Fuel Pump Duty Ratio (D4)
      Injection Mode
      Short FT B1S1
      Long FT B1S1

      HINT: 

      The A/C switch and all accessory switches should be off, and the shift lever should be in the P position, and the engine should be fully warmed up.

      Result

      Item Proceed to
      Injection Mode High Pressure Fuel Pump Duty Ratio (D4) Total of Short FT B1S1 and Long FT B1S1
      Direct 10 to 50% - A
      50% or higher -20% or less B
      10% or less +20% or higher
      50% or higher +20% or higher C
      10% or less -20% or less D

      HINT: 

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

      Refer to INITIALIZATION [10/2021 - ]

    Result: 

    REPLACE FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE) 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    See step  8

    Result: 

    REPLACE ECM 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    See step  6

  6. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION MODE (DIRECT)) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Mode
      Data List Display
      High Pressure Fuel Pump Duty Ratio (D4)
      Injection Mode
      Short FT B1S1
      Long FT B1S1

      HINT: 

      The A/C switch and all accessory switches should be off, and the shift lever should be in the P position, and the engine should be fully warmed up.

      Result

      Item Proceed to
      Injection Mode High Pressure Fuel Pump Duty Ratio (D4) Total of Short FT B1S1 and Long FT B1S1
      Direct 10 to 50% -25% or less A
      10 to 50% +25% or higher
      10 to 50% -25 to +25% B

      HINT: 

      Perform "Inspection After Repair" after replacing the direct fuel injector assembly.

      Refer to INITIALIZATION [10/2021 - ]

    Result: 

    REPLACE DIRECT FUEL INJECTOR ASSEMBLY 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    CHECK FOR INTERMITTENT PROBLEMS 

    Refer to CHECK FOR INTERMITTENT PROBLEMS [12/2019 - ]

  7. CHECK MISFIRE COUNT OF DIRECT INJECTION 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Mode
      Data List Display
      Injection Mode
      Misfire Count Cylinder #1
      Misfire Count Cylinder #2
      Misfire Count Cylinder #3
      Misfire Count Cylinder #4

      HINT: 

      The A/C switch and all accessory switches should be off, and the shift lever should be in the P position, and the engine should be fully warmed up.

      Result

      Injection Mode Misfire Count Proceed to
      Direct No misfire counts, or misfire counts occur randomly in all cylinders A
      Misfire counts occur in particular cylinder B

      HINT: 

      Perform "Inspection After Repair" after replacing the direct fuel injector assembly.

      Refer to INITIALIZATION [10/2021 - ]

    Result: 

    REPLACE DIRECT FUEL INJECTOR ASSEMBLY 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    See step  8

  8. REPLACE FUEL (ENGINE ROOM SIDE) PUMP ASSEMBLY (FOR HIGH PRESSURE SIDE) 

    Refer to REMOVAL [10/2022 - 11/2023]

    HINT: 

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

    Refer to INITIALIZATION [10/2021 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  9

  9. CLEAR DTC 
    1. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    2. Turn the ignition switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  10

  10. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0171-00, P0172-00, P1170-00 and/or P117B-00 is output B

    Result: 

    END 

    Result: 

    REPLACE ECM 

    Refer to REMOVAL [10/2022 - 11/2023]

  11. INSPECT PORT FUEL INJECTOR ASSEMBLY 
    1. Check the injection volume (whether fuel volume is high or low, and whether injection pattern is poor).

      Refer to INSPECTION [12/2019 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the port fuel injector assembly.

      Refer to INITIALIZATION [10/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    NG 

    REPLACE PORT FUEL INJECTOR ASSEMBLY 

    Refer to REMOVAL [10/2022 - 11/2023]

  12. CHECK PCV VALVE AND HOSE CONNECTIONS 
    GTY769136Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Check the PCV hose connections.
    2. Check the PCV valve.

      Refer to INSPECTION [12/2019 - ]

      OK

      PCV hose and PCV valve are connected correctly and are not damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE PCV VALVE OR HOSE 

    Result: 

    OK 

    See step  13

  13. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks.

      Refer to ON-VEHICLE INSPECTION [12/2019 - ]

      OK

      No leaks in intake system.

      HINT: 

      Perform "Inspection After Repair" after repairing or replacing the intake system.

      Refer to INITIALIZATION [10/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE INTAKE SYSTEM 

    Result: 

    OK 

    See step  14

  14. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. Idle the engine for 5 minutes or more with the shift lever in P.
    4. Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Volume for A/F Sensor
      Data List Display
      A/F (O2) Sensor Current B1S1
      A/F (O2) Sensor Current B1S2
    5. Monitor the output values of the air fuel ratio sensor (sensor 1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2) displayed on the GTS.

      HINT: 

      • The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.
      • The air fuel ratio sensor (sensor 1) has an output delay of a few seconds and the air fuel ratio sensor (sensor 2) has a maximum output delay of approximately 20 seconds.
      • If the sensor output value does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

      Standard

      GTS Display (Sensor) Injection Volume Status Voltage
      A/F (O2) Sensor Current B1S1
      (Air fuel ratio (sensor 1))
      12.5% Rich Below -0.075 mA
      -12.5% Lean More than 0.037 mA
      A/F (O2) Sensor Current B1S2
      (Air fuel ratio (sensor 2))
      12.5% Rich Below -0.86 mA
      -12.5% Lean More than 0.33 mA

      Result

      Status A/F (O2) Sensor Current B1S1 Status A/F (O2) Sensor Current B1S2 Air Fuel Ratio Condition and Air Fuel Ratio Sensor Condition Suspected Trouble Area Proceed to
      Lean/Rich Lean/Rich Normal - A
      Lean Lean Actual air fuel ratio lean
      • PCV valve and hose
      • PCV hose connections
      • Gas leak from exhaust system
      • Intake system
      • Fuel pressure
      • Mass air flow meter sub-assembly
      • Engine coolant temperature sensor
      • EGR valve assembly
      Rich Rich Actual air fuel ratio rich
      • Gas leak from exhaust system
      • Ignition system
      • Fuel pressure
      • Mass air flow meter sub-assembly
      • Engine coolant temperature sensor
      • EGR valve assembly
      Lean Lean/Rich Air fuel ratio sensor (sensor 1) malfunction
      • Air fuel ratio sensor (sensor 1)
      B
      Rich Lean/Rich Air fuel ratio sensor (sensor 1) malfunction
      • Air fuel ratio sensor (sensor 1)
      1. Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1) is consistently more than 0.037 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2) is consistently more than 0.33 mA.
      2. Rich: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1) is consistently below -0.075 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2) is consistently below -0.86 mA.
      3. Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output current of the air fuel ratio sensor (sensor 1) or air fuel ratio sensor (sensor 2) alternate correctly.

      HINT: 

      Refer to "Data List / Active Test" [A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2].

      Refer to DATA LIST / ACTIVE TEST [10/2022 - 11/2023]

    Result: 

    See step  24

    Result: 

    See step  15

  15. READ VALUE USING GTS (COOLANT TEMPERATURE) 
    1. Read the Data List twice, when the engine is both cold and warmed up.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature

      Standard

      GTS Display Condition Specified Condition
      Coolant Temperature Cold engine Same as ambient air temperature
      Warm engine Between 75 and 100°C (167 and 212°F)

      HINT: 

      Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.

      Refer to INITIALIZATION [10/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    OK 

    See step  16

  16. PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature

      HINT: 

      The A/C switch and all accessories should be off.

    3. Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the EGR Step Position
      Data List Display
      Intake Manifold Absolute Pressure
      Engine Independent
      NOTE:
      • Do not leave the EGR valve open for 10 seconds or more during the Active Test.
      • Be sure to return the EGR valve to step 0 when the Active Test is completed.
      • Do not open the EGR valve 30 steps or more during the Active Test.

      OK

      The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".

      Standard

      - Control the EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Intake Manifold Absolute Pressure
      (Data List)
      (EGR valve is fully closed) Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

      HINT: 

      • If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
      • While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
      • Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  18

    Result: 

    NG 

    See step  17

  17. INSPECT EGR VALVE ASSEMBLY 
    1. Remove the EGR valve assembly.

      Refer to REMOVAL [10/2022 - 11/2023]

    2. Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

      HINT: 

      Perform "Inspection After Repair" after replacing the EGR valve assembly.

      Refer to INITIALIZATION [10/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    OK 

    See step  18

  18. READ VALUE USING GTS (MASS AIR FLOW SENSOR) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. Read Mass Air Flow Sensor while maintaining an engine speed of 2500 rpm.

      Powertrain > Engine > Data List 

      Tester Display
      Engine Speed
      Mass Air Flow Sensor

      HINT: 

      During charge control, the engine speed is set at idle. Therefore, the engine speed will not increase when the accelerator pedal is depressed. In this case, read the Data List after charge control has completed.

      Standard

      GTS Display Condition Specified Condition
      Mass Air Flow Sensor
      • Engine warmed up
      • Shift position: P
      • A/C: Off
      • Engine Speed: 2500 rpm
      Between 6.2 and 18.6 gm/sec

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  31

    Result: 

    OK 

    See step  19

  19. CHECK FUEL PRESSURE (FOR LOW PRESSURE SIDE) 

    Refer to PROCEDURE - Step 2

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  23

    Result: 

    OK 

    See step  20

  20. CHECK FOR EXHAUST GAS LEAK 
    1. Check for exhaust gas leaks.

      OK

      No gas leaks.

      HINT: 

      Perform "Inspection After Repair" after repairing or replacing the exhaust system.

      Refer to INITIALIZATION [10/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE EXHAUST SYSTEM 

    Result: 

    OK 

    See step  21

  21. INSPECT SPARK PLUG 

    Refer to PROCEDURE - Step 3

    HINT: 

    Perform "Inspection After Repair" after replacing the spark plug.

    Refer to INITIALIZATION [10/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPARK PLUG 

    Refer to PROCEDURE - Step 3

    Result: 

    OK 

    See step  22

  22. CHECK FOR SPARK (SPARK TEST) 
    1. Perform a spark test.

      Refer to PROCEDURE - Step 1

      HINT: 

      • If the result of the spark test is normal, proceed to the next step.
      • Perform "Inspection After Repair" after replacing the spark plug or ignition coil assembly.

        Refer to INITIALIZATION [10/2021 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  31

  23. CHECK FUEL LINE 

    Check the fuel lines for leaks or blockage.

    Result

    Proceed to
    OK
    NG

    Result: 

    OK 

    GO TO FUEL PUMP CONTROL CIRCUIT 

    Refer to Fuel Pump Control Circuit [10/2021 - 11/2024]

    Result: 

    NG 

    REPAIR OR REPLACE FUEL SYSTEM 

  24. INSPECT AIR FUEL RATIO SENSOR (SENSOR 1) (HEATER RESISTANCE) 

    Refer to INSPECTION [12/2019 - ]

    HINT: 

    Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).

    Refer to INITIALIZATION [10/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) 

    Refer to REMOVAL [12/2019 - ]

    Result: 

    OK 

    See step  25

  25. CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR (SENSOR 1)) 
    GTY846590Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Air Fuel Ratio Sensor (Sensor 1))
    1. Disconnect the air fuel ratio sensor (sensor 1) 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 Condition Specified Condition
      C45-2 (+B) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  34

    Result: 

    OK 

    See step  26

  26. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (SENSOR 1) - ECM) 
    1. Disconnect the air fuel ratio sensor (sensor 1) 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
      C45-1 (HA1A) - C55-9 (HA1A) Always Below 1 Ω
      C45-3 (A1A+) - C55-95 (A1A+) Always Below 1 Ω
      C45-4 (A1A-) - C55-94 (A1A-) Always Below 1 Ω
      C45-1 (HA1A) or C55-9 (HA1A) - Body ground and other terminals Always 10 kΩ or higher
      C45-3 (A1A+) or C55-95 (A1A+) - Body ground and other terminals Always 10 kΩ or higher
      C45-4 (A1A-) or C55-94 (A1A-) - 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  27

  27. REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) 

    Refer to REMOVAL [12/2019 - ]

    HINT: 

    Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).

    Refer to INITIALIZATION [10/2021 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  28

  28. CLEAR DTC 
    1. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    2. Turn the ignition switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  29

  29. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0171-00, P0172-00, P1170-00 and/or P117B-00 is output B

    Result: 

    END 

    Result: 

    See step  30

  30. READ VALUE USING GTS (MASS AIR FLOW SENSOR) 
    1. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    2. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    3. Read Mass Air Flow Sensor while maintaining an engine speed of 2500 rpm.

      Powertrain > Engine > Data List 

      Tester Display
      Engine Speed
      Mass Air Flow Sensor

      HINT: 

      During charge control, the engine speed is set at idle. Therefore, the engine speed will not increase when the accelerator pedal is depressed. In this case, read the Data List after charge control has completed.

      Standard

      GTS Display Condition Specified Condition
      Mass Air Flow Sensor
      • Engine warmed up
      • Shift position: P
      • A/C: Off
      • Engine Speed: 2500 rpm
      Between 6.2 and 18.6 gm/sec

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  31

  31. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) 
    1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM.

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [12/2019 - ]

      HINT: 

      Repair any problems.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  32

  32. CLEAR DTC 
    1. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    2. Turn the ignition switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  33

  33. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171-00, P0172-00, P1170-00 OR P117B-00) 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0171-00, P0172-00, P1170-00 and/or P117B-00 is output B

    Result: 

    END 

    Result: 

    See step  38

  34. INSPECT EFI-MAIN NO. 2 RELAY 

    Refer to PROCEDURE - Step 2

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE EFI-MAIN NO. 2 RELAY 

    Result: 

    OK 

    See step  35

  35. CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 2 RELAY) 
    GTY912480Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 EFI-MAIN NO. 2 Relay
    1. Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 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 (AUXILIARY BATTERY - EFI-MAIN NO. 2 RELAY) 

    Result: 

    OK 

    See step  36

  36. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - BODY GROUND) 
    1. Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 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  37

  37. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - AIR FUEL RATIO SENSOR (SENSOR 1)) 
    1. Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the air fuel ratio sensor (sensor 1) 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) - C45-2 (+B) Always Below 1 Ω
      5 (EFI-MAIN NO. 2 relay) or C45-2 (+B) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 2 RELAY) 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  38. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 
    1. Disconnect the mass air flow meter sub-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
      C30-3 (VCC) - C55-78 (VCVG) Always Below 1 Ω
      C30-1 (FG) - C55-101 (VG) Always Below 1 Ω
      C30-2 (E2G) - C55-79 (E2G) Always Below 1 Ω
      C30-3 (VCC) or C55-78 (VCVG) - Body ground and other terminals Always 10 kΩ or higher
      C30-1 (FG) or C55-101 (VG) - Body ground and other terminals Always 10 kΩ or higher
      C30-2 (E2G) or C55-79 (E2G) - 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  39

  39. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  40

  40. CLEAR DTC 
    1. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    2. Turn the ignition switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  41

  41. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0171-00, P0172-00, P1170-00 and/or P117B-00 is output B

    Result: 

    END 

    Result: 

    REPLACE ECM 

    Refer to REMOVAL [10/2022 - 11/2023]