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Home >> Nissan-Datsun >> 2004 >> Sentra SE-R >> Repair and Diagnosis >> External Pages >> Different car >> Section 1057 (Engine Control System) >> DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306: Multiple Cylinder Misfire, No. 1 - 6 Cylinder Misfire >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2004 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.
  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 

    1. OK: GO TO 2.
    2. NG: Discover air leak location and repair.
  2. CHECK FOR EXHAUST SYSTEM CLOGGING 

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

    OK or NG 

    1. OK: GO TO 3.
    2. 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: Displaying Active Test
      G00775671Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

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

    Yes or No 

    1. Yes: GO TO 4.
    2. No: GO TO  7 .
      Fig 2: Disconnecting Injector Harness Connector
      G00775672Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK INJECTOR 

    Does each injector make an operating sound at idle?

    Yes or No 

    1. Yes: GO TO 5.
    2. No: Check injector(s) and circuit(s). Refer to INJECTOR CIRCUIT  .
      Fig 3: Checking Injector
      G00775673Courtesy of NISSAN MOTOR CO., U.S.A.
  5. CHECK IGNITION SPARK 
    1. Remove ignition coil assembly from rocker cover.
    2. Remove spark plug from ignition coil assembly
    3. Connect a known good spark plug to the ignition coil.
    4. Place end of spark plug against a suitable ground and crank engine.
    5. Check for spark.

    OK or NG 

    1. OK: GO TO 6.
    2. NG: Check ignition coil, power transistor and their circuits. Refer to IGNITION SIGNAL  .
      Fig 4: Identifying Ignition Coil
      G00775674Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK SPARK PLUGS 

    Remove the spark plugs and check for fouling, etc.

    OK or NG 

    1. OK: GO TO 7.
    2. NG: Repair or replace spark plug(s) with standard type one(s).
      Fig 5: Checking Spark Plugs
      G00775675Courtesy of NISSAN MOTOR CO., U.S.A.
  7. CHECK COMPRESSION PRESSURE 

    Check compression pressure. Refer to CHECKING COMPRESSION PRESSURE .

    OK or NG 

    1. OK: GO TO 8.
    2. NG: Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
  8. 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. Refer to FUEL PRESSURE CHECK  .
      1. At idle: Approx. 350 kPa (3.57 kg  cm2, 51 psi  )

    OK or NG 

    1. OK: GO TO  10 .
    2. NG: GO TO 9.
  9. DETECT MALFUNCTIONING PART 

    Check the following.

  10. CHECK IGNITION TIMING 

    Check the following items. Refer to BASIC INSPECTION  .

    Fig 6: Item Specification Chart
    G00775676Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 11.
    2. NG: Follow the BASIC INSPECTION  .
  11. CHECK A/F SENSOR 1 INPUT SIGNAL 
    1. Turn ignition switch OFF.
    2. Disconnect A/F sensor 1 harness connector.
      Fig 7: Disconnecting A/F Sensor 1 Harness Connector
      G00775677Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Disconnect ECM harness connector.
    4. Check harness continuity between the following terminals.

      Refer to WIRING DIAGRAM  .

      Fig 8: Harness Continuity Between Terminals
      G00775678Courtesy of NISSAN MOTOR CO., U.S.A.
      1. Continuity should exist. 
    5. Check harness continuity between the following terminals and ground. Refer to WIRING DIAGRAM  .
      Fig 9: Harness Continuity Between Terminals Chart
      G00775679Courtesy of NISSAN MOTOR CO., U.S.A.
      1. Continuity should not exist. 
    6. Also check harness for short to power.

    OK or NG 

    1. OK: GO TO 12.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors between ECM and A/F sensor 1.
  12. CHECK A/F SENSOR 1 HEATER 

    Refer to COMPONENT INSPECTION  .

    OK or NG 

    1. OK: GO TO 13.
    2. NG: Replace A/F sensor 1.
  13. CHECK MASS AIR FLOW SENSOR 

    With CONSULT-II 

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

    1. 2.0 - 6.0 g.m/sec: at idling 
    2. 7.0 - 20.0 g.m/sec: at 2,500 RPM 

    With GST 

    Check mass air flow sensor signal in MODE 1 with GST.

    1. 2.0 - 6.0 g.m/sec: at idling 
    2. 7.0 - 20.0 g.m/sec: at 2,500 RPM 

    OK or NG 

    1. OK: GO TO 14.
    2. NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or body grounds. Refer to DTC P0101 MAF SENSOR  .
  14. CHECK SYMPTOM MATRIX CHART 

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

    OK or NG 

    1. OK: GO TO 15.
    2. NG: Repair or replace.
  15. ERASE THE 1ST TRIP DTC 

    Some tests may cause a 1 st 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  .

    1. GO TO 16.
  16. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  .

    1. INSPECTION END 
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