LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2007 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P1225 To P2A03 >> DTC P2122, P2123 App Sensor >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body.

      Refer to "GROUND INSPECTION ".

      Fig 1: Checking Ground Connections
      G04900129Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT 
    1. Disconnect accelerator pedal position (APP) sensor harness connector.
    2. Turn ignition switch ON.
      Fig 2: Checking APP Sensor 1 Power Supply Circuit
      G04900579Courtesy of NISSAN NORTH AMERICA, INC.
    3. Check voltage between APP sensor terminal 7 and ground with CONSULT-II or tester.

      Voltage: Approximately 5V 

      Fig 3: Checking Voltage Between APP Sensor Terminal 7 And Ground
      G04900580Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 3.

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

  3. CHECK APP SENSOR 1 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.

      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 4.

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

  4. CHECK APP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check harness continuity between ECM terminal 106 and APP sensor terminal 2.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO 5.

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

  5. CHECK APP SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO  7.

    NG: GO TO 6.

  6. 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 

  7. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    INSPECTION END