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Home >> Nissan-Datsun >> 2004 >> Sentra Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - QG18DE >> Ignition Signal >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK ENGINE START 

    Turn ignition switch OFF, and restart engine.

    Is engine running? 

    Yes or No 

    1. Yes (With CONSULT-II) :GO TO 2.
    2. Yes (Without CONSULT-II) : GO TO  3.
    3. No : GO TO  4.
  2. CHECK OVERALL FUNCTION 

    With CONSULT-II 

    1. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-II.
    2. Make sure that each circuit produces a momentary engine speed drop.
      Fig 1: Displaying ACTIVE TEST Mode
      G00773387Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : INSPECTION END 
    2. NG : GO TO  10.
  3. CHECK OVERALL FUNCTION 

    Without CONSULT-II 

    1. Let engine idle.
    2. Read the voltage signal between ECM terminals 61, 62, 80, 81 and ground with an oscilloscope.
    3. Verify that the oscilloscope screen shows the signal wave as shown below.
      Fig 2: Voltage Signal Wave Form
      G00773388Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 3: Checking Voltage Between ECM Terminals 61, 62, 80, 81 And Ground
      G00773389Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : INSPECTION END 
    2. NG : GO TO  10
  4. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I 
    1. Turn ignition switch ON.
    2. Check voltage between ECM terminals 119, 120 and ground with CONSULT-II or tester.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK : GO TO 5.
    2. NG : Go to POWER SUPPLY CIRCUIT FOR ECM 
    Fig 4: Checking Voltage Between ECM Terminals 119, 120 And Ground
    G00773390Courtesy of NISSAN MOTOR CO., U.S.A.
  5. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II 
    1. Turn ignition switch OFF.
    2. Disconnect condenser harness connector.
    3. Turn ignition switch ON.
    4. Check voltage between condenser terminal 1 and ground with CONSULT-II or tester.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK : GO TO  10.
    2. NG : GO TO 6.
    Fig 5: Checking Voltage Between Condenser Terminal 1 And Ground
    G00773391Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III 
    1. Turn ignition switch OFF.
    2. Disconnect ECM relay.
    3. Check harness continuity between ECM relay terminal 7 and condenser terminal 1.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    4. Also check harness for short to ground and short to power.
      Fig 6: Disconnecting ECM Relay
      G00773392Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : GO TO 7.
    2. NG : Repair open circuit or short to ground or short to power in harness or connectors.
  7. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-IV 

    Check voltage between ECM relay terminal 6 and ground with CONSULT-II or tester.

    1. Voltage: Battery voltage 

    OK or NG 

    1. OK : GO TO  9.
    2. NG : GO TO 8.
    Fig 7: Checking Voltage Between ECM Relay Terminal 6 And Ground
    G00773393Courtesy of NISSAN MOTOR CO., U.S.A.
  8. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E10, F48
    • 15A fuse
    • Harness for open or short between ECM relay and battery
      1. : Repair or replace harness or connectors.
  9. CHECK ECM RELAY 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO  17.
    2. NG : Replace ECM relay.
  10. CHECK CONDENSER GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect condenser harness connector.
    3. Check harness continuity between condenser terminal 2 and ground.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    4. Also check harness for short to power.

    OK or NG 

    1. OK : GO TO 11.
    2. NG : Repair open circuit or short to power in harness or connector.
  11. CHECK CONDENSER 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 12.
    2. NG : Replace condenser.
  12. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-V 
    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Disconnect ignition coil harness connector.
    4. Turn ignition switch ON.
      Fig 8: Identifying Ignition Coil With Power Transistor
      G00773394Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Check voltage between ignition coil terminal 3 and ground with CONSULT-II or tester.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK : GO TO  14.
    2. NG : GO TO 13.
    Fig 9: Checking Voltage Between Ignition Coil Terminal 3 And Ground
    G00773395Courtesy of NISSAN MOTOR CO., U.S.A.
  13. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness for open or short between ignition coil and ECM relay
      1. : Repair open circuit or short to ground or short to power in harness or connectors.
  14. CHECK IGNITION COIL GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Check harness continuity between ignition coil terminal 2 and engine ground.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    3. Also check harness for short to power.

    OK or NG 

    1. OK : GO TO 15.
    2. NG : Repair open circuit or short to power in harness or connectors.
  15. CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminals 61, 62, 80, 81 and ignition coil terminal 1.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    3. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK : GO TO 16.
    2. NG : Repair open circuit or short to ground or short to power in harness or connectors.
  16. CHECK IGNITION COIL WITH POWER TRANSISTOR 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 17.
    2. NG : Replace ignition coil with power transistor.
  17. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    1. INSPECTION END 

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