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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 69 (Engine Control System - Diagnostic Codes (P0420-P0450)) >> SFI System >> DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1 [08/2023 - ] >> Procedure

DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1 [08/2023 - ]: Procedure

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

      Powertrain > Engine > Trouble Codes 

      Result

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

      HINT: 

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

    Result: 

    A 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2023 - 10/2024]  , or Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2024 - ] 

    Result: 

    B 

    See step  2

  2. READ FREEZE FRAME DATA (LONG FT B1S2) 
    1. Using the GTS, read the value displayed in the Freeze Frame Data.

      Powertrain > Engine > DTC(P0420-00) > Freeze Frame Data 

      Tester Display
      Long FT B1S2

      Result

      Result Proceed to
      The value of Long FT B1S2 is less than 1.0 % A
      The value of Long FT B1S2 is 1.0 % or more B

    Result: 

    B 

    See step  84

    Result: 

    A 

    See step  3

  3. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR) 

    Pre-procedure1

    • Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    • Start the engine and warm it up until the engine coolant temperature is 80°C (176°F) or higher.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    • Idle the engine for 5 minutes or more with P selected.
    • Change the fuel injection volume using the GTS, 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 GTS.

      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

      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 GTS.
      • 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

      GTS 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 [08/2023 - ]

    Post-procedure1

    • None.

    Result: 

    B 

    See step  7

    Result: 

    C 

    See step  8

    Result: 

    D 

    See step  10

    Result: 

    A 

    See step  4

  4. 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  80

    Result: 

    OK 

    See step  5

  5. PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION) 

    Pre-procedure1

    • Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    • 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.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    • 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:
      • Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
      • 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

    Post-procedure1

    • None.

    Result: 

    OK 

    See step  83

    Result: 

    NG 

    See step  6

  6. INSPECT EGR VALVE ASSEMBLY 

    Pre-procedure1

    • Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    OK 

    See step  83

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

  7. REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  8. 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  80

    Result: 

    OK 

    See step  9

  9. REPLACE AIR FUEL RATIO SENSOR (SENSOR 2) 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  10. 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  80

    Result: 

    OK 

    See step  11

  11. PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION) 

    Pre-procedure1

    • Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    • 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.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature
    • 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:
      • Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
      • 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

    Post-procedure1

    • None.

    Result: 

    OK 

    See step  13

    Result: 

    NG 

    See step  12

  12. INSPECT EGR VALVE ASSEMBLY 

    Pre-procedure1

    • Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    OK 

    See step  13

  13. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION MODE) 

    Refer to PROCEDURE - Step 2

    Result

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

    Result: 

    B 

    See step  17

    Result: 

    C 

    See step  30

    Result: 

    D 

    See step  33

    Result: 

    A 

    See step  14

  14. CHECK IF VEHICLE HAS RUN OUT OF FUEL IN PAST 

    Refer to PROCEDURE - Step 3

    Result

    Result Proceed to
    YES A
    NO B

    Result: 

    B 

    See step  16

    Result: 

    A 

    See step  15

  15. DTC CAUSED BY RUNNING OUT OF FUEL 

    HINT: 

    DTC caused by running out of fuel.

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  16. CHECK FOR INTERMITTENT PROBLEMS 

    HINT: 

    Refer to CHECK FOR INTERMITTENT PROBLEMS [10/2022 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  17. READ VALUE USING GTS (FUEL PRESSURE (HIGH)) 

    Refer to PROCEDURE - Step 4

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  24

    Result: 

    OK 

    See step  18

  18. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION MODE (DIRECT)) 

    Refer to PROCEDURE - Step 5

    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

    Result: 

    B 

    See step  22

    Result: 

    C 

    See step  25

    Result: 

    D 

    See step  23

    Result: 

    A 

    See step  19

  19. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION MODE (DIRECT)) 

    Refer to PROCEDURE - Step 6

    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

    Result: 

    B 

    See step  21

    Result: 

    A 

    See step  20

  20. REPLACE DIRECT FUEL INJECTOR ASSEMBLY 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  21. CHECK FOR INTERMITTENT PROBLEMS 

    HINT: 

    Refer to CHECK FOR INTERMITTENT PROBLEMS [10/2022 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  22. REPLACE FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE) 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  23. REPLACE ECM 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  24. CHECK MISFIRE COUNT OF DIRECT INJECTION 

    Refer to PROCEDURE - Step 7

    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

    Result: 

    B 

    See step  28

    Result: 

    A 

    See step  25

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

    Refer to PROCEDURE - Step 8

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  26

  26. CLEAR DTC 

    Refer to PROCEDURE - Step 9

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  27

  27. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

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

    Post-procedure1

    • None.

    Result: 

    A 

    See step  81

    Result: 

    B 

    See step  29

  28. REPLACE DIRECT FUEL INJECTOR ASSEMBLY 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  29. REPLACE ECM 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  30. INSPECT PORT FUEL INJECTOR ASSEMBLY 

    Refer to PROCEDURE - Step 11

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  32

    Result: 

    OK 

    See step  31

  31. REPLACE ECM 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  32. REPLACE PORT FUEL INJECTOR ASSEMBLY 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  33. CHECK PCV VALVE AND HOSE CONNECTIONS 

    Refer to PROCEDURE - Step 12

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  79

    Result: 

    OK 

    See step  34

  34. CHECK INTAKE SYSTEM 

    Refer to PROCEDURE - Step 13

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  78

    Result: 

    OK 

    See step  35

  35. PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR) 

    Refer to PROCEDURE - Step 14

    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)

    Result: 

    B 

    See step  51

    Result: 

    A 

    See step  36

  36. READ VALUE USING GTS (COOLANT TEMPERATURE) 

    Refer to PROCEDURE - Step 15

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  44

    Result: 

    OK 

    See step  37

  37. PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION) 

    Refer to PROCEDURE - Step 16

    Result

    Proceed to
    OK
    NG

    Result: 

    OK 

    See step  39

    Result: 

    NG 

    See step  38

  38. INSPECT EGR VALVE ASSEMBLY 

    Refer to PROCEDURE - Step 17

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  50

    Result: 

    OK 

    See step  39

  39. READ VALUE USING GTS (MASS AIR FLOW SENSOR) 

    Refer to PROCEDURE - Step 18

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  81

    Result: 

    OK 

    See step  40

  40. CHECK FUEL PRESSURE (FOR LOW PRESSURE SIDE) 

    Refer to PROCEDURE - Step 19

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  47

    Result: 

    OK 

    See step  41

  41. CHECK FOR EXHAUST GAS LEAK 

    Refer to PROCEDURE - Step 20

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  46

    Result: 

    OK 

    See step  42

  42. INSPECT SPARK PLUG 

    Refer to PROCEDURE - Step 3

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  45

    Result: 

    OK 

    See step  43

  43. CHECK FOR SPARK (SPARK TEST) 

    Refer to PROCEDURE - Step 22

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  59

  44. REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  45. REPLACE SPARK PLUG 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  47. CHECK FUEL LINE 

    Refer to PROCEDURE - Step 23

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  49

    Result: 

    OK 

    See step  48

  48. GO TO FUEL PUMP CONTROL CIRCUIT 

    HINT: 

    Refer to Fuel Pump Control Circuit [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  49. REPAIR OR REPLACE FUEL SYSTEM 
    1. Repair or replace fuel system.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  50. REPLACE EGR VALVE ASSEMBLY 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

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

    Refer to PROCEDURE - Step 24

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  77

    Result: 

    OK 

    See step  52

  52. CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR (SENSOR 1)) 

    Refer to PROCEDURE - Step 25

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  62

    Result: 

    OK 

    See step  53

  53. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (SENSOR 1) - ECM) 

    Refer to PROCEDURE - Step 26

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  57

    Result: 

    OK 

    See step  54

  54. REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) 

    Refer to PROCEDURE - Step 27

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  55

  55. CLEAR DTC 

    Refer to PROCEDURE - Step 28

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  56

  56. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

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

    Post-procedure1

    • None.

    Result: 

    A 

    See step  81

    Result: 

    B 

    See step  58

  57. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  58. READ VALUE USING GTS (MASS AIR FLOW SENSOR) 

    Refer to PROCEDURE - Step 30

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  59

  59. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) 

    Refer to PROCEDURE - Step 31

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  60

  60. CLEAR DTC 

    Refer to PROCEDURE - Step 32

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  61

  61. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171-00, P0172-00, P1170-00 OR P117B-00) 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

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

    Post-procedure1

    • None.

    Result: 

    A 

    See step  81

    Result: 

    B 

    See step  67

  62. INSPECT EFI-MAIN NO. 2 RELAY 

    Refer to PROCEDURE - Step 34

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  76

    Result: 

    OK 

    See step  63

  63. CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 2 RELAY) 

    Refer to PROCEDURE - Step 35

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  75

    Result: 

    OK 

    See step  64

  64. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - BODY GROUND) 

    Refer to PROCEDURE - Step 36

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  74

    Result: 

    OK 

    See step  65

  65. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - AIR FUEL RATIO SENSOR (SENSOR 1)) 

    Refer to PROCEDURE - Step 37

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  71

    Result: 

    OK 

    See step  66

  66. REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 2 RELAY) 
    1. Repair or replace harness or connector (EFI-MAIN No. 1 relay - EFI-MAIN No. 2 relay).

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  67. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 

    Refer to PROCEDURE - Step 38

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  72

    Result: 

    OK 

    See step  68

  68. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY 

    Refer to PROCEDURE - Step 39

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  69

  69. CLEAR DTC 

    Refer to PROCEDURE - Step 40

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  70

  70. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

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

    Post-procedure1

    • None.

    Result: 

    A 

    See step  81

    Result: 

    B 

    See step  73

  71. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  72. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  73. REPLACE ECM 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  74. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  75. REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - EFI-MAIN NO. 2 RELAY) 
    1. Repair or replace harness or connector (auxiliary Battery - EFI-MAIN No. 2 relay).

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  76. REPLACE EFI-MAIN NO. 2 RELAY 
    1. Replace EFI-MAIN No. 2 relay.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  77. REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  81

  78. REPAIR OR REPLACE INTAKE SYSTEM 
    1. Repair or replace intake system.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  79. REPAIR OR REPLACE PCV VALVE OR HOSE 
    1. Repair or replace PCV valve or hose.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  80. 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 [10/2022 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  81

  81. CLEAR DTC 

    Pre-procedure1

    • None.
    • Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

      Result

      Proceed to
      NEXT

    Post-procedure1

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

    Result: 

    NEXT 

    See step  82

  82. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

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

    Post-procedure1

    • None.

    Result: 

    A 

    END 

    Result: 

    B 

    See step  83

  83. 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).

      HINT: 

      Refer to REMOVAL [08/2023 - ]

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

      HINT: 

      Refer to REMOVAL [08/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  84. CHECK FOR EXHAUST GAS LEAK 

    OK

    No gas leaks in exhaust system.

    HINT: 

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

    Refer to INITIALIZATION [10/2022 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPAIR OR REPLACE EXHAUST SYSTEM 

    Result: 

    OK 

    See step  85

  85. REPLACE AIR FUEL RATIO SENSOR (SENSOR 2) 

    HINT: 

    Refer to REMOVAL [08/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  86

  86. CLEAR DTC 

    Pre-procedure1

    • None.
    • Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

      Result

      Proceed to
      NEXT

    Post-procedure1

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

    Result: 

    NEXT 

    See step  87

  87. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Check for DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      DTCs are not output.

      Result

      Proceed to
      NEXT

    Post-procedure1

    • None.

    Result: 

    NEXT 

    END 

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