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Home >> Infiniti >> 2015 >> QX60 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 40 (Engine Control System (DTC/Circuit Diagnosis) (VQ35DE) (Except Hybrid) (1 Of 3)) >> DTC/Circuit Diagnosis >> Trouble Diagnosis - Specification Value >> Diagnosis Procedure >> Detailed Procedure

Detailed Procedure

WARNING: This page is about a different car, the 2016 Infiniti QX60. However, it is still accessible from the selected car via links, so may be relevant.

  1. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    G-20With CONSULT 

    1. Start engine.
    2. Confirm that the testing conditions are met. Refer to COMPONENT FUNCTION CHECK .
    3. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.
      NOTE:

      Check "A/F ALPHA-B1", "A/F ALPHA-B2" for approximately 1 minute because they may fluctuate. It is NG if the indication is out of the SP value even a little.

    Is the measurement value within the SP value?

    YES 

    GO TO STEP   17  .

    NO-1 

    Less than the SP value: GO TO STEP 2  .

    NO-2 

    More than the SP value: GO TO STEP 3  .

  2. CHECK "B/FUEL SCHDL"

    Select "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    GO TO STEP 4  .

    NO 

    More than the SP value: GO TO STEP   19  .

  3. CHECK "B/FUEL SCHDL"

    Select "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    GO TO STEP 6  .

    NO-1 

    More than the SP value: GO TO STEP   6  .

    NO-2 

    Less than the SP value: GO TO STEP   25  .

  4. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    1. Stop the engine.
    2. Disconnect PCV hose, and then plug it.
    3. Start engine.
    4. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    GO TO STEP 5  .

    NO 

    GO TO STEP 6  .

  5. CHANGE ENGINE OIL

    1. Stop the engine.
    2. Change engine oil.
      NOTE:

      This symptom may occur when a large amount of gasoline is mixed with engine oil because of driving conditions (such as when engine oil temperature does not rise enough since a journey distance is too short during winter). The symptom will not be detected after changing engine oil or changing driving conditions.

    INSPECTION END

  6. CHECK FUEL PRESSURE

    Check fuel pressure. (Refer to WORK PROCEDURE .)

    Is the inspection result normal?

    YES 

    GO TO STEP   9  .

    NO-1 

    Fuel pressure is too high: Replace "fuel filter and fuel pump assembly", refer to REMOVAL AND INSTALLATION , and then GO TO STEP 8  .

    NO-2 

    Fuel pressure is too low: GO TO STEP 7  .

  7. DETECT MALFUNCTIONING PART

    Check fuel hoses and fuel tubes for clogging.

    Is the inspection result normal?

    YES 

    Replace "fuel filter and fuel pump assembly", refer to REMOVAL AND INSTALLATION , and then GO TO STEP 8  .

    NO 

    Repair or replace malfunctioning part and then GO TO STEP 8  .

  8. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    1. Start engine.
    2. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    GO TO STEP 9  .

  9. PERFORM POWER BALANCE TEST

    1. Perform "POWER BALANCE" in "ACTIVE TEST" mode.
    2. Check that the each cylinder produces a momentary engine speed drop.

    Is the inspection result normal?

    YES 

    GO TO STEP 12  .

    NO 

    GO TO STEP 10  .

  10. DETECT MALFUNCTIONING PART

    Check the following below.

    Is the inspection result normal?

    YES 

    Replace fuel injector, refer to REMOVAL AND INSTALLATION , and then GO TO STEP 11  .

    NO 

    Repair or replace malfunctioning part and then GO TO STEP 11  .

  11. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    1. Start engine.
    2. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    GO TO STEP 12  .

  12. CHECK A/F SENSOR 1 FUNCTION

    Perform all DTC CONFIRMATION PROCEDURE related with A/F sensor 1.

    • For DTC P0130, P0150, refer to DTC LOGIC .
    • For DTC P0131, P0151, refer to DTC LOGIC .
    • For DTC P0132, P0152, refer to DTC LOGIC .
    • For DTC P014C, P014D, P014E, P014F, P015A, P015B, P015C, P015D, refer to DTC LOGIC .
    • For DTC P2096, P2097, P2098, P2099, refer to DTC LOGIC .

    Are any DTCs detected?

    YES 

    GO TO STEP 15  .

    NO 

    GO TO STEP 13  .

  13. CHECK A/F SENSOR 1 CIRCUIT

    Perform Diagnostic Procedure according to corresponding DTC.

    GO TO STEP 14  .

  14. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    1. Start engine.
    2. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    GO TO STEP 15  .

  15. DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR

    1. Stop the engine.
    2. Disconnect ECM harness connector. Check pin terminal and connector for damage, and then reconnect it.

    GO TO STEP 16  .

  16. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    1. Start engine.
    2. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    Detect malfunctioning part according to SYMPTOM TABLE .

  17. CHECK "B/FUEL SCHDL"

    Select "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO-1 

    More than the SP value: GO TO STEP 18  .

    NO-2 

    Less than the SP value: GO TO STEP   25  .

  18. DETECT MALFUNCTIONING PART

    1. Check for the cause of large engine friction. Refer to the following.
      • Engine oil level is too high
      • Engine oil viscosity
      • Belt tension of power steering, alternator, A/C compressor, etc. is excessive
      • Noise from engine
      • Noise from transmission, etc.
    2. Check for the cause of insufficient combustion. Refer to the following.
      • Valve clearance malfunction
      • Intake valve timing control function malfunction
      • Camshaft sprocket installation malfunction, etc.

    Repair or replace malfunctioning part, and then GO TO STEP   30  .

  19. CHECK INTAKE SYSTEM

    Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.

    • Crushed air ducts
    • Malfunctioning seal of air cleaner element
    • Uneven dirt of air cleaner element
    • Improper specification of intake air system

    Is the inspection result normal?

    YES 

    GO TO STEP 21  .

    NO 

    Repair or replace malfunctioning part, and then GO TO STEP 20  .

  20. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2", AND "B/FUEL SCHDL"

    Select "A/F ALPHA-B1", "A/F ALPHA-B2", and "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    "B/FUEL SCHDL" is more, "A/F ALPHA-B1", "A/F ALPHA-B2" are less than the SP value: GO TO STEP 21  .

  21. DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR

    1. Stop the engine.
    2. Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and then reconnect it again.

    GO TO STEP 22  .

  22. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2"

    1. Start engine.
    2. Select "A/F ALPHA-B1", "A/F ALPHA-B2" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to DIAGNOSIS PROCEDURE . Then GO TO STEP   29  .

    NO 

    GO TO STEP 23  .

  23. CHECK "MAS AIR FLOW SENSOR (Hz)"

    Select "MAS AIR FLOW SENSOR (Hz)" in "SPEC" of "DATA MONITOR" mode, and check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    GO TO STEP 24  .

    NO 

    More than the SP value: Replace mass air flow sensor, refer to REMOVAL AND INSTALLATION , and then GO TO STEP   29  .

  24. REPLACE ECM

    Replace ECM. Refer to REMOVAL AND INSTALLATION .

    GO TO STEP   29  .

  25. CHECK INTAKE SYSTEM

    Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.

    • Crushed air ducts
    • Malfunctioning seal in air cleaner element
    • Uneven dirt in air cleaner element
    • Improper specification in intake air system

    Is the inspection result normal?

    YES 

    GO TO STEP 27  .

    NO 

    Repair or replace malfunctioning part, and then GO TO STEP 26  .

  26. CHECK "B/FUEL SCHDL"

    Select "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    Less than the SP value: GO TO STEP 27  .

  27. CHECK "MAS AIR FLOW SENSOR (Hz)"

    Select "MAS AIR FLOW SENSOR (Hz)" in "SPEC" of "DATA MONITOR" mode, and check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    GO TO STEP 28  .

    NO 

    Less than the SP value: Replace mass air flow sensor, refer to REMOVAL AND INSTALLATION , and then GO TO STEP 30  .

  28. CHECK INTAKE SYSTEM

    Check for the cause of air leakage after the mass air flow sensor. Refer to the following.

    • Disconnection, looseness, and cracks in air duct
    • Looseness of oil filler cap
    • Disconnection of oil level gauge
    • Open stuck, breakage, hose disconnection, or cracks in PCV valve
    • Disconnection or cracks in EVAP purge hose, stuck open EVAP canister purge volume control solenoid valve
    • Malfunctioning seal in rocker cover gasket
    • Disconnection, looseness, or cracks in hoses, such as a vacuum hose, connecting to intake air system parts
    • Malfunctioning seal in intake air system, etc.

    GO TO STEP 30  .

  29. CHECK "A/F ALPHA-B1", "A/F ALPHA-B2", AND "B/FUEL SCHDL"

    Select "A/F ALPHA-B1", "A/F ALPHA-B2", and "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and check that each indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    Detect malfunctioning part according to SYMPTOM TABLE .

  30. CHECK "B/FUEL SCHDL"

    Select "B/FUEL SCHDL" in "SPEC" of "DATA MONITOR" mode, and then check that the indication is within the SP value.

    Is the measurement value within the SP value?

    YES 

    INSPECTION END

    NO 

    Detect malfunctioning part according to SYMPTOM TABLE .

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