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Home >> Infiniti >> 2004 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> 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

    Yes (With CONSULT-II): GO TO 2.

    Yes (Without CONSULT-II): GO TO  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.

    OK or NG

    OK: INSPECTION END 

    NG: GO TO  10.

    Fig 1: Active Test Mode With CONSULT-II
    G02691905Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK OVERALL FUNCTION 

    Without CONSULT-II 

    1. Let engine idle.
    2. Read the voltage signal between ECM terminals 46, 60, 61, 62, 65, 79, 80, 81 and ground with an oscilloscope.
    3. Verify that the oscilloscope screen shows the signal wave as shown below.
    NOTE: The pulse cycle changes depending on RPM at idle.
    Fig 2: Checking Overall Function Without CONSULT-II
    G02691906Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 3: Overall Function Graphical Representation
    G02691907Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    OK: INSPECTION END 

    NG: GO TO  10.

  4. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I 
    1. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
    2. Check voltage between ECM terminals 119, 120 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    OK: GO TO 5.

    NG: GO TO POWER SUPPLY AND GROUND CIRCUIT .

    Fig 4: Checking Ignition Coil Power Supply Circuit-I
    G02691908Courtesy 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.
      Fig 5: Checking Ignition Coil Power Supply Circuit-II (1 Of 2)
      G02691909Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 6: Checking Ignition Coil Power Supply Circuit-II (2 Of 2)
      G02691910Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between condenser terminal 1 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    OK: GO TO  8.

    NG: GO TO 6.

  6. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III 
    1. Turn ignition switch OFF.
    2. Disconnect IPDM E/R connector E119.
    3. Check harness continuity between IPDM E/R terminal 4 and condenser terminal 1.

      Refer to Wiring Diagram.

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.

    OK or NG

    OK: GO TO POWER SUPPLY AND GROUND CIRCUIT .

    NG: GO TO 7.

  7. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E2, F32
    • Harness for open or short between ignition coil and IPDM E/R

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

  8. CHECK CONDENSER GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Check harness continuity between condenser terminal 2 and engine ground.

      Refer to Wiring Diagram.

      Continuity should exist. 

    3. Also check harness for short to power.

    OK or NG

    OK: GO TO 9.

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

  9. CHECK CONDENSER 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO 10.

    NG: Replace condenser.

  10. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-IV 
    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Disconnect ignition coil harness connector.
      Fig 7: Identifying Ignition Coil & Related Components
      G02691911Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Turn ignition switch ON.
    5. Check voltage between ignition coil terminal 3 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    OK: GO TO  12.

    NG: GO TO 11.

    Fig 8: Checking Voltage Between Terminal
    G02691912Courtesy of NISSAN MOTOR CO., U.S.A.
  11. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E2, F32
    • Harness for open or short between ignition coil and harness connector F32

      : Repair or replace harness or connectors.

  12. 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.

      Continuity should exist. 

    3. Also check harness for short to power.

    OK or NG

    OK: GO TO 13.

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

  13. CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminals 46, 60, 61, 62, 65, 79, 80, 81 and ignition coil terminal 1.

      Refer to Wiring Diagram.

      Continuity should exist. 

    3. Also check harness for short to ground and 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 IGNITION COIL WITH POWER TRANSISTOR 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO 15.

    NG: Replace ignition coil with power transistor.

  15. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    : INSPECTION END 

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