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Home >> Nissan-Datsun >> 2006 >> Sentra SE-R >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System - DTCS P0137 To P0445 (Qr25DE) >> DTC P0300 - P0304 Multiple Cylinder Misfire, No. 1 - 4 Cylinder Misfire >> Diagnostic Procedure

Diagnostic Procedure

  1. 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.

    OK or NG 

    OK: GO TO  2.

    NG: Discover air leak location and repair.

  2. CHECK FOR EXHAUST SYSTEM CLOGGING 

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

    OK or NG 

    OK: GO TO  3.

    NG: Repair or replace it.

  3. PERFORM POWER BALANCE TEST 

    With CONSULT-II 

    1. Perform "POWER BALANCE" in "ACTIVE TEST" mode.
    2. Is there any cylinder which does not produce a momentary engine speed drop?
      Fig 1: Consult-II ACTIVE TEST Display Screen
      G04080452Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    When disconnecting each fuel injector harness connector one at a time, is there any cylinder which does not produce a momentary engine speed drop?

    Fig 2: Disconnecting Each Fuel Injector Harness Connector
    G04191895Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    Yes: GO TO  4.

    No: GO TO  7.

  4. CHECK FUEL INJECTOR 

    Does each fuel injector make an operating sound at idle?

    Fig 3: Checking Fuel Injector For Audible Clicking
    G04132840Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    Yes: GO TO  5.

    No: Check fuel injector(s) and circuit(s). Refer to "FUEL INJECTOR ".

  5. CHECK FUNCTION OF IGNITION COIL-I 
    CAUTION: Do the following procedure in the place where ventilation is good without the combustible.
    1. Turn ignition switch OFF.
    2. Remove fuel pump fuse located in fuse box to release fuel pressure.
      NOTE: Do not use CONSULT-II to release fuel pressure, or fuel pressure applies again during the following procedure.
      3. Fig 4: Removing Fuel Pump Fuse
      G04191897Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Start engine.
    4. After engine stalls, crank it 2 or 3 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 between the edge of the spark plug and grounded metal portion as shown in the figure.
    11. Crank engine for about three seconds, and check whether spark is generated between the spark plug and the grounded metal portion.

      Spark should be generated. 

      12. Fig 5: Checking For Spark Between Spark Plug And Grounded Metal On Engine
      G04074892Courtesy of NISSAN MOTOR CO., U.S.A.
    CAUTION:
    • Do not approach to the spark plug and the ignition coil within 50cm. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20kV or more.
    • It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
    NOTE: When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.

    OK or NG 

    OK: GO TO  9.

    NG: GO TO  6.

  6. CHECK FUNCTION OF IGNITION COIL-II 
    1. Turn ignition switch OFF.
    2. Disconnect spark plug and connect a known-good 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. 

    OK or NG 

    OK: GO TO  7.

    NG: Check ignition coil, power transistor and their circuits. Refer to "IGNITION SIGNAL ".

  7. CHECK SPARK PLUGS 

    Check the spark plugs and check for fouling, etc.

    Fig 6: Checking Initial Spark Plug
    G04185314Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO  8.

    NG: Repair or replace spark plug (s) with standard type one (s). For spark plug type ignition coil. Refer to "CHANGING SPARK PLUGS (DOUBLE PLATINUM - TIPPED TYPE) ".

  8. 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. 

    OK or NG 

    OK: INSPECTION END 

    NG: Replace spark plug(s) with standard type one(s). For spark plug type, refer to "CHANGING SPARK PLUGS (DOUBLE PLATINUM - TIPPED TYPE) ".

  9. CHECK COMPRESSION PRESSURE 

    Check compression pressure.

    Refer to "CHECKING COMPRESSION PRESSURE ".

    OK or NG 

    OK: GO TO  10.

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

  10. CHECK FUEL PRESSURE 
    1. Install all removed parts.
    2. Release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE ".
    3. Install fuel pressure gauge and check fuel pressure.

      At idle: Approximately 350 kPa (3.57 kg/cm 2  , 51 psi) 

    OK or NG 

    OK: GO TO  12.

    NG: GO TO  11.

  11. DETECT MALFUNCTIONING PART 

    Check the following.

  12. CHECK IGNITION TIMING 

    Checking the following items. Refer to "BASIC INSPECTION ".

    ITEM SPECIFICATIONS

    Items Specifications
    Target idle speed M/T 700 +/- 50 rpm (in Neutral position)
    A/T 700 +/- 50 rpm (in P or N position)
    Ignition timing M/T 15 +/- 5° BTDC (in Neutral position)
    A/T 15 +/- 5° BTDC (in P or N position)

    OK or NG 

    OK: GO TO  13.

    NG: Follow the "BASIC INSPECTION ".

  13. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector and A/F sensor 1 harness connector.
      3. Fig 7: Disconnecting ECM Harness Connector And A/F Sensor 1 Harness Connector
      G04191900Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
      ECM TERMINAL REFERENCE

      A/F sensor 1 terminal ECM terminal
      1 16
      5 35
      6 56
      2 75

      Continuity should exist. 

    4. Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to WIRING DIAGRAM .

      Continuity should not exist. 

    5. Also check harness for short to power.

    OK or NG 

    OK: GO TO  14.

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

  14. CHECK A/F SENSOR 1 HEATER 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO  15.

    NG: Replace A/F sensor 1.

  15. CHECK MASS AIR FLOW SENSOR 

    With CONSULT-II 

    Check "MASS AIR FLOW" in "DATA MONITOR" mode with CONSULT-II.

    1.0 - 4.0 g.m/sec: at idling 

    4.0 - 10.0 g.m/sec: at 2, 500 rpm 

    With GST 

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

    1.0 - 4.0 g.m/sec: at idling 

    4.0 - 10.0 g.m/sec: at 2, 500 rpm 

    OK or NG 

    OK: GO TO  16.

    NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to "DTC P0101 MAF SENSOR ".

  16. CHECK SYMPTOM MATRIX CHART 

    Check items on the rough idle symptom in "SYMPTOM MATRIX CHART ".

    OK or NG 

    OK: GO TO  17.

    NG: Repair or replace.

  17. 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 "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION ".

    : GO TO  18.

  18. CHECK INTERMITTENT INCIDENT 

    Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    : INSPECTION END 

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