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Home >> Toyota >> 2019 >> Sequoia SR5, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 15 (Engine Control System (3UR-FBE) - Diagnostic Codes (3 Of 6)) >> SFI System >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2) [10/2016 - 08/2018] >> Procedure

DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2) [10/2016 - 08/2018]: Procedure

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  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 OR P0430) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read DTCs.
      RESULT

      Result Proceed to
      DTC P0420 or P0430 is output A
      DTC P0420 or P0430 and other DTCs are output B

      HINT: 

      If any DTCs other than P0420 or P0430 are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DTC CHART 

    Refer to:

    DIAGNOSTIC TROUBLE CODE CHART [10/2016 - 08/2017]

    DIAGNOSTIC TROUBLE CODE CHART [08/2017 - 08/2018]

    Result: 

    A 

    See step  2

  2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Turn the Techstream on.
    4. Warm up the engine and run the engine at an engine speed of 2500 rpm for approximately 90 seconds.
    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
    6. Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.
    7. Monitor the voltage outputs of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

      HINT: 

      • Change the fuel injection volume within the range of -12.5% to +12.5%.
      • The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
      • If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
      Techstream Display (Sensor) Injection Volume Status Voltage
      AFS Voltage B1S1 or AFS Voltage B2S1
      (Air fuel ratio)      		 +12.5% Rich Below 3.1 V
      -12.5% Lean Higher than 3.4 V
      O2S B1S2 or O2S B2S2
      (Heated oxygen)      		 +12.5% Rich Higher than 0.55 V
      -12.5% Lean Below 0.4 V
      RESULT

      Status of AFS Voltage B1S1 or AFS Voltage B2S1 Status of O2S B1S2 or O2S B2S2 Air Fuel Ratio Condition and Air Fuel Ratio and Heated Oxygen Sensor Condition Suspected Trouble Area Proceed to
      Lean/Rich Lean/Rich Normal
      • Three-way catalytic converter
      • Gas leaks from exhaust system
      		 A
      Lean Lean/Rich Air fuel ratio sensor malfunction Air fuel ratio sensor B
      Rich Lean/Rich Air fuel ratio sensor malfunction Air fuel ratio sensor B
      Lean/Rich Lean Heated oxygen sensor malfunction
      • Heated oxygen sensor
      • Gas leaks from exhaust system
      		 C
      Lean/Rich Rich Heated oxygen sensor malfunction
      • Heated oxygen sensor
      • Gas leaks from exhaust system
      		 C
      Lean Lean Actual air fuel ratio lean
      • Extremely rich or lean actual air fuel ratio
      • Gas leaks from exhaust system
      		 D
      Rich Rich Actual air fuel ratio rich
      • Extremely rich or lean actual air fuel ratio
      • Gas leaks from exhaust system
      		 D

      Lean: During the Control the Injection Volume Active Test, the air fuel ratio sensor output voltage (AFS Voltage) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S) is consistently below 0.4 V.

      Rich: During the Control the Injection Volume Active Test, the AFS Voltage is consistently below 3.1 V, and the O2S is consistently higher than 0.55 V.

      Lean/Rich: During the Control the Injection Volume Active Test, the output voltage of the air fuel ratio sensor and heated oxygen sensor alternate correctly.

    8. Refer to "Data List / Active Test" [AFS Voltage B1S1, AFS Voltage B2S1, O2S B1S2 and O2S B2S2]. Refer to:

      DATA LIST / ACTIVE TEST [08/2015 - 08/2017]

      DATA LIST / ACTIVE TEST [08/2017 - 08/2018]

    Result: 

    B 

    See step  7

    Result: 

    C 

    See step  5

    Result: 

    D 

    See step  6

    Result: 

    A 

    See step  3

  3. CHECK FOR EXHAUST GAS LEAK 
    1. Check for exhaust gas leaks from the exhaust manifold sub-assembly and exhaust pipes.

      OK

      No gas leaks.

    Result: 

    NG 

    See step  8

    Result: 

    OK 

    See step  4

  4. CHECK DTC OUTPUT (DTC P0420 AND/OR P0430) 
    NOTE:
    • When DTC P0420 is output, replace the front No. 2 exhaust pipe assembly (TWC: Front catalyst and rear catalyst) when catalyst replacement is necessary.
    • When DTC P0430 is output, replace the front exhaust pipe assembly (TWC: Front catalyst and rear catalyst) when catalyst replacement is necessary.

    HINT: 

    Confirm the replacement parts, referring to the illustration in the Catalyst Location.

    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream ON.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read the DTCs.
      RESULT

      Result Proceed to
      DTC P0420 is output A
      DTC P0430 is output B
      DTC P0420 and P0430 are output A and B

    Result: 

    B 

    REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST) 

    (Refer to REMOVAL [08/2015 - 08/2018] )

    Result: 

    A 

    REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST) 

    (Refer to REMOVAL [08/2015 - 08/2018] )

  5. CHECK FOR EXHAUST GAS LEAK 
    1. Check for exhaust gas leaks from the exhaust manifold assembly and exhaust pipes.

      OK

      No gas leaks.

    Result: 

    OK 

    See step  9

    Result: 

    NG 

    See step  8

  6. CHECK FOR EXHAUST GAS LEAK 
    1. Check for exhaust gas leaks from the exhaust manifold assembly and exhaust pipes.

      OK

      No gas leaks.

    Result: 

    OK 

    See step  10

    Result: 

    NG 

    See step  8

  7. REPLACE AIR FUEL RATIO SENSOR 
    1. Replace the air fuel ratio sensor (Refer to REMOVAL [08/2015 - 08/2018] ).

      HINT: 

      Perform "Inspection After Repair" after replacing the air fuel ratio sensor. Refer to:

      INITIALIZATION [08/2015 - 08/2017]

      INITIALIZATION [08/2017 - 08/2018]

    Result: 

    NEXT 

    See step  11

  8. REPAIR OR REPLACE FOR EXHAUST GAS LEAK POINT 
    1. Repair or replace exhaust gas leak point.

      HINT: 

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

      INITIALIZATION [08/2015 - 08/2017]

      INITIALIZATION [08/2017 - 08/2018]

    Result: 

    NEXT 

    See step  11

  9. REPLACE HEATED OXYGEN SENSOR 
    1. Replace the heated oxygen sensor (Refer to REMOVAL [08/2015 - 08/2018] ).

      HINT: 

      Perform "Inspection After Repair" after replacing the heated oxygen sensor. Refer to;

      INITIALIZATION [08/2015 - 08/2017]

      INITIALIZATION [08/2017 - 08/2018]

    Result: 

    NEXT 

    See step  11

  10. CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR-FUEL RATIO 
    1. Check the cause of extremely rich or lean actual air fuel ratio, referring to the Fuel Injection System Inspection Procedure. Refer to:

      Fuel Injection System [08/2015 - 08/2017]

      Fuel Injection System [08/2017 - 08/2018]

    Result: 

    NEXT 

    See step  11

  11. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream ON.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [08/2015 - 08/2018] ).
    5. Turn the ignition switch off and wait for at least 30 seconds.
    6. Start the engine.
    7. Turn the Techstream on.
    8. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    10. Read the DTCs.
      RESULT

      Result Proceed to
      DTC P0420 and/or P0430 is output A
      DTC is not output B

    Result: 

    B 

    END 

    Result: 

    A 

    See step  12

  12. CHECK DTC OUTPUT (DTC P0420 AND/OR P0430) 
    NOTE:
    • When DTC P0420 is output, replace the front No. 2 exhaust pipe assembly (TWC: Front catalyst and rear catalyst) when catalyst replacement is necessary.
    • When DTC P0430 is output, replace the front exhaust pipe assembly (TWC: Front catalyst and rear catalyst) when catalyst replacement is necessary.

    HINT: 

    Confirm the replacement parts, referring to the illustration in the Catalyst Location.

    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream ON.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read the DTCs.
      RESULT

      Result Proceed to
      DTC P0420 is output A
      DTC P0430 is output B
      DTC P0420 and P0430 are output A and B

    Result: 

    B 

    REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST) 

    (Refer to REMOVAL [08/2015 - 08/2018] )

    Result: 

    A 

    REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST) 

    (Refer to REMOVAL [08/2015 - 08/2018] )

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