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Home >> Infiniti >> 2021 >> Q50 Pure, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (3 Of 6) >> Engine (ECM) >> P0301 Misfire >> DTC Diagnosis Procedure >> VR30DDTT engine

VR30DDTT engine

  1. CHECK GROUND CONNECTION 

    Check the following.

    • Connection condition of the ground F52
    • Connection condition of the ground harness between engine assembly and vehicle body (If equipped)

    Is the inspection result normal?

    YES

    GO TO 2

    NO

    Repair or replace error-detected parts.

  2. CHECK FOR INTAKE AIR LEAK AND PCV HOSE 
    1. Start engine and run it at idle speed.
    2. Listen for the sound of the intake air leak.
    3. Check PCV hose connection.

    Is intake air leak detected?

    YES

    Discover air leak location and repair.

    NO

    GO TO 3.

  3. CHECK FOR EXHAUST SYSTEM CLOGGING 

    Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.

    Is the inspection result normal?

    YES

    With CONSULT: GO TO 4.

    YES

    Without CONSULT: GO TO 5.

    NO

    Repair or replace it.

  4. PERFORM POWER BALANCE TEST 

    SYMBOL With CONSULT

    1. Start engine.
    2. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT.
    3. Make sure that each circuit produces a momentary engine speed drop.

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    GO TO 5.

  5. CHECK FUNCTION OF FUEL INJECTOR-I 
    1. Start engine and let it idle.
    2. Listen to each fuel injector operation sound.
      G04812223Courtesy of NISSAN NORTH AMERICA, INC.

      Clicking sound should be heard.

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Perform trouble diagnosis for FUEL INJECTOR, Refer to Diagnosis Procedure .

  6. CHECK FUNCTION OF IGNITION COIL-I 
    CAUTION: Perform the following procedure in a place where with no combustible objects and good ventilation.
    1. Turn ignition switch OFF.
    2. Remove fuel pump fuse SYMBOL in IPDM E/R SYMBOL to release fuel pressure.
      GNSJMBIA0021Z-021Courtesy of NISSAN NORTH AMERICA, INC.
      NOTE: Do not use CONSULT to release fuel pressure, or fuel pressure applies again during the following procedure.
    3. Start engine.
    4. After engine stalls, crank it two or three times to release all fuel pressure.
    5. Turn ignition switch OFF.
    6. Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
    7. Remove ignition coil and spark plug of the cylinder to be checked.
    8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
    9. Connect spark plug and harness connector to ignition coil.
    10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal portion as shown in the figure, below.
      G04886523Courtesy of NISSAN NORTH AMERICA, INC.
    11. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal portion.

      Spark should be generated.
      CAUTION:
      • Never place the spark plug and the ignition coil within 50 cm (19.7 in) each other. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.
      • It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
      NOTE: When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunctioning.

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    GO TO 7.

  7. CHECK FUNCTION OF IGNITION COIL-II 
    1. Turn ignition switch OFF.
    2. Disconnect spark plug and connect a non-malfunctioning spark plug.
    3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.

      Spark should be generated.

    Is the inspection result normal?

    YES

    GO TO 8.

    NO

    Check ignition coil, power transistor and their circuits. Refer to Diagnosis Procedure .

  8. CHECK SPARK PLUG 

    Check the initial spark plug for fouling, etc.

    G04185314Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES

    Replace spark plug(s) with standard type one(s). For spark plug type, Refer to SPARK PLUG : Removal & Installation .

    NO

    Repair or clean spark plug. Then GO TO 9.

  9. CHECK FUNCTION OF IGNITION COIL-III 
    1. Reconnect the initial spark plugs.
    2. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.

      Spark should be generated.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Replace spark plug(s) with standard type one(s). For spark plug type, Refer to SPARK PLUG : Removal & Installation .

  10. CHECK COMPRESSION PRESSURE 

    Check compression pressure. Refer to Inspection .

    Is the inspection result normal?

    YES

    GO TO 11.

    NO

    Check pistons, piston rings, valves, valve seats and cylinder head gaskets.

  11. CHECK FUEL PRESSURE 
    1. Install all removed parts.
    2. Release fuel pressure to zero. Refer to Work Procedure .
    3. Install fuel pressure gauge and check fuel pressure. Refer to Work Procedure .

    Is the inspection result normal?

    YES

    GO TO 13.

    NO

    GO TO 12.

  12. DETECT MALFUNCTIONING PART 

    Check fuel hoses and fuel tubes for clogging.

    Is the inspection result normal?

    YES

    Replace "fuel filter and fuel pump assembly".

    NO

    Repair or replace.

  13. CHECK IDLE SPEED AND IGNITION TIMING 

    For procedure, Refer to Work Procedure .

    For specification, Refer to IDLE SPEED : Service Data and IGNITION TIMING : Service Data .

    Is the inspection result normal?

    YES

    GO TO 14.

    NO

    Refer to Work Procedure .

  14. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect corresponding A/F sensor 1 harness connector.
    3. Disconnect ECM harness connector.
    4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

      Bank

      +

      -

      Continuity

      A/F sensor 1

      ECM

      Connector

      Terminal

      Connector

      Terminal

      1

      F133

      3

      F142

      102

      Existed

      4

      101

      2

      F134

      3

      106

      4

      105
    5. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

      Bank

      +

      -

      Continuity

      A/F sensor 1

      Connector

      Terminal

      1

      F133

      3

      Ground

      Not existed

      4

      2

      F134

      3

      4

      Bank

      +

      -

      Continuity

      ECM

      Connector

      Terminal

      1

      F142

      101

      Ground

      Not existed

      102

      2

      105

      106
    6. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 15.

    NO

    Repair open circuit, short to ground or short to power in harness or connectors.

  15. CHECK A/F SENSOR 1 HEATER 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    GO TO 16.

    NO

    Replace (malfunctioning) A/F sensor 1. Refer to TURBOCHARGER : Exploded View .

  16. CHECK MASS AIR FLOW SENSOR 

    SYMBOL With CONSULT

    Check mass air flow sensor signal in "DATA MONITOR" mode with CONSULT.

    For specification, Refer to Component Inspection .

    SYMBOL With GST

    Check mass air flow sensor signal in Service $01 with GST.

    For specification, Refer to MASS AIR FLOW SENSOR : Service Data .

    Is the measurement value within the specification?

    YES

    GO TO 17.

    NO

    Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to DTC Diagnosis Procedure .

  17. CHECK SYMPTOM TABLE 

    Check items on the rough idle symptom in Symptom Table .

    Is the inspection result normal?

    YES

    GO TO 18.

    NO

    Repair or replace.

  18. ERASE THE 1ST TRIP DTC 

    Some tests may cause a 1st trip DTC to be set.

    Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to Diagnosis Description (Without CONSULT) or Diagnosis Description (With CONSULT).

    INSPECTION END

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