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Home >> Infiniti >> 2005 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> 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 

    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.

    OK or NG 

    1. OK: INSPECTION END
    2. NG: GO TO  10.
    Fig 1: CONSULT-II Display - "POWER BALANCE" In "ACTIVE TEST" Mode
    G02389395Courtesy 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: Voltage Signal Pulse Graph
      G02389396Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 3: Measuring Voltage Between ECM Terminals And Ground
      G02389397Courtesy 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 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.
      Fig 4: Checking Ignition Coil Power Supply Circuit-I
      G02389398Courtesy of NISSAN MOTOR CO., U.S.A.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK: GO TO 5.
    2. NG: Go to "POWER SUPPLY AND GROUND CIRCUIT ".
  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: Identifying Brake Fluid Reservoir And Condenser
      G02389399Courtesy of NISSAN MOTOR CO., U.S.A.
    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  8.
    2. NG: GO TO 6.
    Fig 6: Checking Voltage Between Condenser Terminal 1 And Ground
    G02389400Courtesy of NISSAN MOTOR CO., U.S.A.
  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 .
      1. Continuity should exist. 
    4. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: Go to "POWER SUPPLY AND GROUND CIRCUIT ".
    2. 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
      1. 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 ground. Refer to WIRING DIAGRAM .
      1. Continuity should exist. 
    3. Also check harness for short to power.

    OK or NG 

    1. OK: GO TO 9.
    2. NG: Repair open circuit or short to power in harness or connectors.
  9. CHECK CONDENSER 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    1. OK: GO TO 10.
    2. NG: Replace condenser.
  10. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-IV 
    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
      Fig 7: Identifying Ignition Coil Harness Connector
      G02389401Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Disconnect ignition coil harness connector.
    4. Turn ignition switch ON.
    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  12.
    2. NG: GO TO 11.
    Fig 8: Checking Voltage Between Ignition Coil Terminal 3 And Ground
    G02389402Courtesy 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
      1. 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 .
      1. Continuity should exist. 
    3. Also check harness for short to power.

    OK or NG 

    1. OK: GO TO 13.
    2. 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 .

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

    OK or NG 

    1. OK: GO TO 14.
    2. 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 

    1. OK: GO TO 15.
    2. NG: Replace ignition coil with power transistor.
  15. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    1. : INSPECTION END 
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