LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2021 >> QX80 Premium Select, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (1 Of 5) >> Engine (ECM) >> DTC P0139: Ho2S2 >> Confirmation Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Confirmation Procedure

  1. INSPECTION START 

    Do you have CONSULT?

    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:

    For better results, perform "DTC WORK SUPPORT" at a temperature of 0 to 30 deg.C (32 to 86 deg.F).

    GO TO 3.

  3. PERFORM DTC CONFIRMATION PROCEDURE 

    SYMBOL With CONSULT

    1. Turn ignition switch ON and select "DATA MONITOR" mode with CONSULT.
    2. Start engine and warm it up to the normal operating temperature.
    3. Turn ignition switch OFF and wait at least 10 seconds.
    4. Turn ignition switch ON.
    5. Turn ignition switch OFF and wait at least 10 seconds.
    6. Start engine and keep the engine speed between 3, 500 and 4, 000 rpm for at least 1 minute under no load.
    7. Let engine idle for 1 minute.
    8. Make sure that "COOLAN TEMP/S" indicates more than 70 deg.C (158 deg.F).
    9. Drive the vehicle in a proper gear at 60 km/h (38 MPH) and maintain the speed.
      CAUTION: Always drive vehicle at a safe speed.
    10. Release the accelerator pedal fully at least 5 seconds.
      CAUTION:
      • Enable the engine brake.
      • Always drive carefully.
      • Never apply brake when releasing the accelerator pedal.
    11. Repeat step 9 and 10 at least 8 times.
    12. Check the following item of "DATA MONITOR".

      DTC

      Data monitor item

      Status

      P0139

      HO2 S2 DIAG1 (B1)

      CMPLT

      HO2 S2 DIAG2 (B1)

      P0159

      HO2 S2 DIAG1 (B2)

      HO2 S2 DIAG2 (B2)

    Is "CMPLT" displayed on CONSULT screen?

    YES

    GO TO 6.

    NO

    Perform DTC confirmation procedure again.

    NO

    GO TO 4.

  4. PERFORM DTC WORK SUPPORT 
    1. Open engine hood.
    2. Select "HO2S2 (B1) P0139" or "HO2S2 (B2) P0159" of "HO2S2" in "DTC WORK SUPPORT" mode with CONSULT.
    3. Start engine and follow the instruction of CONSULT display.
      NOTE: It will take at most 10 minutes until "COMPLETED" is displayed.

    Is "COMPLETED" displayed on CONSULT screen?

    YES

    GO TO 6.

    NO

    GO TO 5.

  5. PERFORM DTC CONFIRMATION PROCEDURE AGAIN 
    1. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
    2. Perform DTC confirmation procedure again.

    GO TO 3.

  6. PERFORM SELF-DIAGNOSIS 

    SYMBOL With CONSULT

    Perform ECM self-diagnosis.

    Is DTC "P0139" or "P0159" detected?

    YES

    Refer to DTC Diagnosis Procedure .

    NO

    INSPECTION END

  7. PERFORM COMPONENT FUNCTION CHECK 

    Perform component function check. Refer to Component Function Check .

    NOTE: Use component function check to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Refer to DTC Diagnosis Procedure .

scientia non olet · About LEMON Manuals