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Home >> Infiniti >> 2021 >> Q60 Pure, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (4 Of 7) >> Engine (ECM) >> DTC P0420: Three Way Catalyst Function >> Confirmation Procedure
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Confirmation Procedure

  1. INSPECTION START 

    Do you have CONSULT?

    YES

    GO TO 2.

    NO

    GO TO 7.

  2. PRECONDITIONING 

    If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Turn ignition switch ON.
    3. Turn ignition switch OFF and wait at least 10 seconds.

    TESTING CONDITION:

    Do not hold engine speed for more than the specified minutes below.

    GO TO 3.

  3. PERFORM DTC CONFIRMATION PROCEDURE-I 

    SYMBOL With CONSULT

    1. Turn ignition switch ON.
    2. On CONSULT screen, select "ENGINE">>"Data Monitor".
    3. Start engine and warm it up to the normal operating temperature.
    4. Turn ignition switch OFF and wait at least 10 seconds.
    5. Turn ignition switch ON.
    6. Turn ignition switch OFF and wait at least 10 seconds.
    7. Start engine and keep the engine speed between 3, 500 and 4, 000 rpm for at least 1 minute under no load.
    8. Let engine idle for 1 minute.
    9. Make sure that "COOLAN TEMP/S" indicates more than 70 deg.C (158 deg.F).

      If not, warm up engine and go to next step when "COOLAN TEMP/S" indication reaches 70 deg.C (158 deg.F).

    10. Open engine hood.
    11. On CONSULT screen, select "DTC & SRT CONFIRMATION">>"SRT WORK SUPPORT".
    12. Rev engine up to about 2, 000 rpm and hold it for 3 consecutive minutes then release the accelerator pedal completely.
    13. Check the indication of "CATALYST".

    Which is displayed on CONSULT screen?

    CMPLT

    GO TO 6.

    INCMP

    GO TO 4.

  4. PERFORM DTC CONFIRMATION PROCEDURE-II 
    1. Wait 5 seconds at idle.
    2. Rev engine up to about 2, 000 rpm and maintain it until "INCMP" of "CATALYST" changes to "CMPLT" (It will take approximately 5 minutes).

    Does the indication change to "CMPLT"?

    YES

    GO TO 6.

    NO

    GO TO 5.

  5. PERFORM DTC CONFIRMATION PROCEDURE AGAIN 
    1. Stop engine and cool it down to less than 70 deg.C (158 deg.F).
    2. Perform DTC CONFIRMATION PROCEDURE again.

    GO TO 3.

  6. PERFORM DTC CONFIRMATION PROCEDURE-III 

    Check 1st trip DTC.

    Is DTC P0420 detected?

    YES

    Refer to DTC Diagnosis Procedure .

    NO

    To check malfunction symptom before repair: Refer to Inspection .

    NO

    Confirmation after repair: INSPECTION END

  7. PERFORM COMPONENT FUNCTION CHECK 
    NOTE: Use component function check to check the overall function of the three way catalyst (manifold). During this check, a 1st trip DTC might not be confirmed.

    SYMBOL Without CONSULT

    1. Start engine and warm it up to the normal operating temperature.
    2. Turn ignition switch OFF and wait at least 10 seconds.
    3. Start engine and keep the engine speed between 3, 500 and 4, 000 rpm for at least 1 minute under no load.
    4. Let engine idle for 1 minute.
    5. Open engine hood.
    6. Check the voltage between ECM harness connector terminals under the following condition.

      ECM

      Condition

      Voltage

      Connector

      +

      -

      Terminal

      F143

      49

      [HO2S2 (bank 1)]

      81

      Keeping engine speed at 2, 500 rpm constant under no load

      The voltage fluctuation cycle takes more than 5 seconds.

      • 1 cycle: 0.6 - 1.0 -> 0 - 0.3 -> 0.6 - 1.0

    Is the inspection result normal?

    YES

    To check malfunction symptom before repair: Refer to Inspection .

    YES

    Confirmation after repair: INSPECTION END

    NO

    Refer to DTC Diagnosis Procedure .

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