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Home >> Toyota >> 2020 >> RAV4 Adventure >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (A25A-FKS) (W/O Canister Pump Module) - Diagnostic Codes (2 Of 4) >> SFI SYSTEM (w/o Canister Pump Module) >> DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1 [11/2018 - 08/2020] >> Procedure
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DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1 [11/2018 - 08/2020]: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420-00) 
    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 / Trouble Codes.
    5. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTC P0420-00 is output A
      DTC P0420-00 and other DTCs are output B

      HINT: 

      If any DTCs other than P0420-00 are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2018 - 08/2020] 

    Result: 

    A 

    See step  2

  2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME FOR A/F SENSOR) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
    5. Warm up the air fuel ratio sensors at an engine speed of 2500 rpm for 90 seconds.
    6. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / Data List / Coolant Temperature, A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Injection Volume for A/F Sensor
      Data List Display
      Coolant Temperature
      A/F (O2) Sensor Current B1S1
      A/F (O2) Sensor Current B1S2
    7. Change the fuel injection volume using the Techstream, and monitor the output current of the air fuel ratio sensor (sensor 1) (A/F (O2) Sensor Current B1S1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S2) displayed on the Techstream.

      HINT: 

      • The Active Test "Control the Injection Volume for A/F Sensor" can be used to lower the fuel injection volume by 12.5% or increase the injection volume by 12.5%.
      • The air fuel ratio sensor (sensor 1) is displayed as A/F (O2) Sensor Current B1S1, and the air fuel ratio sensor (sensor 2) is displayed as A/F (O2) Sensor Current B1S2 on the Techstream.
      • 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 current does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

      Standard

      Techstream Display
      (Sensor)      		 Injection Volume Status Current
      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 Actual air fuel ratio, air fuel ratio sensor (sensor 1) and air fuel ratio sensor (sensor 2) condition Main Suspected Trouble Area Proceed to
      Lean/Rich Lean/Rich Normal
      • Three-way catalytic converter
      • Gas leak from exhaust system
      • EGR valve assembly
      		 A
      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)
      Lean/Rich Lean Air fuel ratio sensor (sensor 2) malfunction
      • Air fuel ratio sensor (sensor 2)
      • Gas leak from exhaust system
      		 C
      Lean/Rich Rich Air fuel ratio sensor (sensor 2) malfunction
      • Air fuel ratio sensor (sensor 2)
      • Gas leak from exhaust system
      Lean Lean Actual air fuel ratio lean
      • Extremely lean actual air fuel ratio
      • Gas leak from exhaust system
      • EGR valve assembly
      		 D
      Rich Rich Actual air fuel ratio rich
      • Extremely rich actual air fuel ratio
      • Gas leak from exhaust system
      • EGR valve assembly
      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, A/F (O2) Sensor Current B1S2].

      Refer to DATA LIST / ACTIVE TEST [11/2018 - 08/2020]

    Result: 

    B 

    See step  6

    Result: 

    C 

    See step  7

    Result: 

    D 

    See step  9

    Result: 

    A 

    See step  3

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

      OK

      No gas leaks in exhaust system.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  4

  4. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

      HINT: 

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

    5. Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Engine Speed, Intake Manifold Absolute Pressure and Coolant Temperature.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the EGR Step Position
      Data List Display
      Engine Speed
      Intake Manifold Absolute Pressure
      Coolant Temperature
    6. Check the engine idling condition and Intake Manifold Absolute Pressure values in the Data List while performing the Active Test.
      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 and Engine Speed change in response to EGR step position.

      Standard

      - Control the EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Idling condition Steady idling Idling changes from steady to rough idling or engine stalls
      Intake Manifold Absolute Pressure
      (Data List)      		 Intake Manifold Absolute Pressure value is 20 to 40 kPa(abs)
      (2.9 to 5.8 psi(abs))
      (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: 

      During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  16

    Result: 

    NG 

    See step  5

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

      Refer to REMOVAL [11/2018 - 08/2020]

    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 [11/2018 - 08/2020]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  16

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [11/2018 - 08/2020] 

  6. REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) 
    1. Replace the air fuel ratio sensor (sensor 1).

      Refer to REMOVAL [11/2018 - 08/2020]

      HINT: 

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

      Refer to INITIALIZATION [11/2018 - 08/2020]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  14

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

      OK

      No gas leaks in exhaust system.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  8

  8. REPLACE AIR FUEL RATIO SENSOR (SENSOR 2) 
    1. Replace the air fuel ratio sensor (sensor 2).

      Refer to REMOVAL [11/2018 - 08/2020]

      HINT: 

      Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 2).

      Refer to INITIALIZATION [11/2018 - 08/2020]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  14

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

      OK

      No gas leaks in exhaust system.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  10

  10. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

      HINT: 

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

    5. Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Engine Speed, Intake Manifold Absolute Pressure and Coolant Temperature.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the EGR Step Position
      Data List Display
      Engine Speed
      Intake Manifold Absolute Pressure
      Coolant Temperature
    6. Check the engine idling condition and Intake Manifold Absolute Pressure values in the Data List while performing the Active Test.
      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 and Engine Speed change in response to EGR step position.

      Standard

      - Control the EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Idling condition Steady idling Idling changes from steady to rough idling or engine stalls
      Intake Manifold Absolute Pressure
      (Data List)      		 Intake Manifold Absolute Pressure value is 20 to 40 kPa(abs)
      (2.9 to 5.8 psi(abs))
      (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: 

      During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  12

    Result: 

    NG 

    See step  11

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

      Refer to REMOVAL [11/2018 - 08/2020]

    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 [11/2018 - 08/2020]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [11/2018 - 08/2020] 

    Result: 

    OK 

    See step  12

  12. 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 DTC P0171-00 and P0172-00 Inspection Procedure.

      Refer to 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 [11/2018 - 08/2020]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  14

  13. REPAIR OR REPLACE EXHAUST SYSTEM 
    1. Repair or replace exhaust system.

      HINT: 

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

      Refer to INITIALIZATION [11/2018 - 08/2020]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  14

  14. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  15

  15. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Enter the following menus: Powertrain / Engine / Trouble Codes.
    3. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0420-00 is output B

    Result: 

    A 

    END 

    Result: 

    B 

    See step  16

  16. REPLACE EXHAUST MANIFOLD (TWC: FRONT CATALYST) AND FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) 
    NOTE:

    When replacing the exhaust manifold and the front exhaust pipe assembly in order to replace the three-way catalytic converter, it is not necessary to replace the air fuel ratio sensor (sensor 1) and the air fuel ratio sensor (sensor 2).

    HINT: 

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

    1. Replace the exhaust manifold (TWC: Front catalyst).

      Refer to REMOVAL [11/2018 - 02/2019] , or refer to REMOVAL [02/2019 - 08/2020]

    2. Replace the front exhaust pipe assembly (TWC: Rear catalyst).

      Refer to REMOVAL [11/2018 - 02/2019] , or refer to REMOVAL [02/2019 - 08/2020]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

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