LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2009 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Component Testing >> Ignition Signal >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

  1. CHECK ENGINE START

    Turn ignition switch OFF, and restart engine.

    Is engine running? 

    Yes or No 

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

    Yes (Without CONSULT-III): GO TO  3.

    No: GO TO  4.

  2. CHECK OVERALL FUNCTION

    With CONSULT-III 

    1. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-III.
    2. Make sure that each circuit produces a momentary engine speed drop.

      OK or NG 

      OK: INSPECTION END 

      NG: GO TO  10.

  3. CHECK OVERALL FUNCTION

    Without CONSULT-III 

    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 1: ECM Terminals Signal Waveform
      G06315866Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 2: Checking Voltage Signal Between ECM Terminals And Ground
      G06315867Courtesy 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-III or tester.

      Voltage: Battery voltage 

      OK or NG 

      OK: GO TO 5.

      NG: GO TO POWER SUPPLY AND GROUND CIRCUIT .

      Fig 3: Checking Voltage Between ECM Terminals 119, 120 And Ground
      G06315868Courtesy of NISSAN MOTOR CO., U.S.A.
  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 4: Identifying Condenser-1 Harness Connector
      G06315869Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between condenser-1 terminal 1 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

      OK or NG 

      OK: GO TO  8.

      NG: GO TO 6.

      Fig 5: Checking Voltage Between Condenser-1 Terminal 1 And Ground
      G06315870Courtesy 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-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 6: Identifying Ignition Coils Harness Connector
      G06315871Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Turn ignition switch ON.
    5. Check voltage between ignition coil terminal 3 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

      OK or NG 

      OK: GO TO  12.

      NG: GO TO 11.

      Fig 7: Checking Voltage Between Ignition Coil Terminal 3 And Ground
      G06315872Courtesy 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 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 "HOW TO CHECK TERMINAL "and "INTERMITTENT INCIDENT ".

    INSPECTION END 

scientia non olet · About LEMON Manuals