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Home >> Infiniti >> 2007 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Component Testing >> 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: CONSULT-II Display - ACTIVE TEST
    G04900123Courtesy of NISSAN NORTH AMERICA, INC.
  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 Voltage Signal Between ECM Terminals 46 And Ground
      G04900809Courtesy of NISSAN NORTH AMERICA, INC.
      Fig 3: Checking Overall Function
      G04900810Courtesy of NISSAN NORTH AMERICA, INC.

    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 

      Fig 4: Checking Voltage Between ECM Terminals 119, 120 And Ground
      G04900811Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 5.

    NG: Go to "POWER SUPPLY AND GROUND CIRCUIT ".

  5. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II 
    1. Turn ignition switch OFF.
    2. Disconnect condenser-1 harness connector.
    3. Turn ignition switch ON.
      Fig 5: Checking Ignition Coil Power Supply Circuit-II
      G04900812Courtesy of NISSAN NORTH AMERICA, INC.
    4. Check voltage between condenser-1 terminal 1 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

      Fig 6: Checking Voltage Between Condenser-2 Terminal 1 And Ground
      G04875485Courtesy of NISSAN NORTH AMERICA, INC.

    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-1 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 condenser-1 and IPDM E/R

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

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

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 10.

    NG: Replace condenser-1.

  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
      G04900814Courtesy of NISSAN NORTH AMERICA, INC.
    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 Ignition Coil Terminal 3 And Ground
    G04875257Courtesy of NISSAN NORTH AMERICA, INC.
  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 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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