2004 Infiniti QX56 AWDFACTORY OEM SERVICE PROCEDURE

Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten ground three screws on the body.
      Fig 1: Checking Ground Connections
      G02691893Courtesy of NISSAN MOTOR CO., U.S.A.

    Refer to GROUND INSPECTION .

    OK or NG

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. CHECK APP SENSOR POWER SUPPLY CIRCUIT 
    1. Disconnect accelerator pedal position (APP) sensor harness connector.
    2. Turn ignition switch ON.
      Fig 2: Checking APP Sensor Power Supply Circuit (1 Of 2)
      G02691894Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between APP sensor terminals 6, 7 and ground with CONSULT-II or tester.

      Voltage: Approximately 5V 

    OK or NG

    OK: GO TO  7.

    NG: GO TO 3.

    Fig 3: Checking APP Sensor Power Supply Circuit (2 Of 2)
    G02691895Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-II 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between APP sensor terminal 7 and ECM terminal 91. Refer to Wiring Diagram.

      Continuity should exist. 

    OK or NG

    OK: GO TO 4.

    NG: Repair open circuit.

  4. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-II 

    Check the following.

    • Harness for short to power and short to ground, between the following terminals
    CHECKING HARNESS BETWEEN TERMINALS

    ECM terminal Sensor terminal
    47 Electric throttle control actuator terminal 2
    91 APP sensor terminal 7

    OK or NG

    OK: GO TO 5.

    NG: Repair short to ground or short to power in harness connectors.

  5. CHECK THROTTLE POSITION SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO  11.

    NG: GO TO 6.

  6. REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR 
    1. Replace the electric throttle control actuator.
    2. Perform THROTTLE VALVE CLOSED POSITION LEARNING .
    3. Perform IDLE AIR VOLUME LEARNING .

      : INSPECTION END 

  7. CHECK APP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between ECM terminal 82 and APP sensor terminal 1, ECM terminal 83 and APP sensor terminal 3.

      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 8.

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

  8. CHECK APP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check harness continuity between ECM terminal 106 and APP sensor terminal 2, ECM terminal 98 and APP sensor terminal 5.
    2. 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 9.

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

  9. CHECK ACCELERATOR PEDAL POSITION SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO  11.

    NG: GO TO 10.

  10. REPLACE ACCELERATOR PEDAL ASSEMBLY 
    1. Replace the accelerator pedal assembly.
    2. Perform ACCELERATOR PEDAL RELEASED POSITION LEARNING .
    3. Perform THROTTLE VALVE CLOSED POSITION LEARNING .
    4. Perform IDLE AIR VOLUME LEARNING .

      : INSPECTION END 

  11. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    : INSPECTION END 

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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