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Home >> Infiniti >> 2005 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P2122, P2123: App Sensor >> Diagnostic Procedure
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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 Connection
      G02389349Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 2.
    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: Locating Accelerator Pedal Position Sensor
      G02389350Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between APP sensor terminal 7 and ground with CONSULT-II or tester.
      1. Voltage: Approximately 5V 

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
    Fig 3: Checking Voltage Between APP Sensor Terminal 7 & Ground
    G02389351Courtesy of NISSAN MOTOR CO., U.S.A.
  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 .

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

    OK or NG 

    1. OK: GO TO 4.
    2. 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 .

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

    OK or NG 

    1. OK: GO TO 5.
    2. 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 

    1. OK: GO TO  5.
    2. 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 ".
      1. INSPECTION END 
    5. CHECK INTERMITTENT INCIDENT 

      Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

      1. INSPECTION END