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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 1164 (Engine Control System - QG18DE) >> DTC P0300 To P0304: No. 1 - 4 Cylinder Misfire, Multiple Cylinder Misfire >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2004 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR INTAKE AIR LEAK 
    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 (manifold) 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: CONSULT-II Display Active Test
      G00772782Courtesy 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?

    Fig 2: Identifying Injector Harness Connector
    G00772783Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes: GO TO 4.
    2. No: GO TO  7.
  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 .
      Fig 3: Checking Injector
      G00772784Courtesy 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 ignition coil.
    4. Place and of spark plug against a suitable ground 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: Checking Ignition Spark
      G00772785Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK SPARK PLUGS

    Check 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). For spark plug type ignition coil. Refer to OUTER COMPONENT PARTS .
      Fig 5: Identifying Spark Plugs
      G00772786Courtesy 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.

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

    OK or NG 

    1. OK: GO TO  10.
    2. NG: GO TO 9.
      Fig 6: Identifying Fuel Pressure Gauge
      G00772787Courtesy of NISSAN MOTOR CO., U.S.A.
  9. DETECT MALFUNCTIONING PART

    Check the following.

    • Fuel pump and circuit (Refer to FUEL PUMP .)
    • Fuel pressure regulator
    • Fuel lines
    • Fuel filter for clogging
      1. Repair or replace.
  10. CHECK IGNITION TIMING

    Perform BASIC INSPECTION .

    Fig 7: Ignition Timing Chart
    G00772788Courtesy 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 CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector and A/F sensor 1 harness connector.
    3. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
      Fig 8: ECM And A/F Sensor 1 Terminal Chart
      G00772789Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should exist. 

      Fig 9: Identifying ECM Harness Connector And A/F Sensor 1 Harness Connector
      G00772790Courtesy of NISSAN MOTOR CO., U.S.A.
    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 

    1. OK: GO TO 12.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
  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" in "DATA MONITOR" mode with CONSULT-II.

    at idling: 1.4 - 4.0 g.m/sec 

    at 2, 500 RPM: 5.0 - 10.0 g.m/sec 

    With GST 

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

    at idling: 1.4 - 4.0 g.m/sec 

    at 2, 500 RPM: 5.0 - 10.0 g.m/sec 

    OK or NG 

    1. OK: GO TO  15.
    2. NG: GO TO 14.
  14. CHECK CONNECTORS 

    Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or engine grounds.

    Refer to DTC P0101 MAF SENSOR .

    OK or NG 

    1. OK: GO TO 15.
    2. NG: Repair or replace it.
  15. CHECK SYMPTOM MATRIX CHART 

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

    OK or NG 

    1. OK: GO TO 16.
    2. NG: Repair or replace.
  16. 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 .

    1. GO TO 17.
  17. CHECK INTERMITTENT INCIDENT

    Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    1. INSPECTION END 
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