LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2004 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> DTC P1229: Sensor Power Supply >> 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 ground three screws on the body
      Fig 1: DTC P1229 Checking Ground Connections
      G02691664Courtesy 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 1 POWER SUPPLY CIRCUIT 
    1. Disconnect accelerator pedal position (APP) sensor harness connector
    2. Turn ignition switch ON
      Fig 2: DTC P1229 Locating Accelerator Pedal Position Sensor Harness Connector
      G02691665Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between APP sensor terminal 6 and ground with CONSULT-II or tester

      Voltage: Approximately 5V 

    OK or NG

    OK: GO TO  5.

    NG: GO TO 3.

    Fig 3: Checking Voltage Between APP Sensor Terminal 6 & Ground
    G02691666Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK SENSOR POWER SUPPLY CIRCUITS 

    Check the following.

    • Harness for short to power and short to ground, between the following terminals
      CHECKING SENSOR POWER SUPPLY CIRCUITS

      ECM terminal Sensor terminal
      48 EVAP control system pressure sensor terminal 3
      49 Refrigerant pressure sensor terminal 1
      68 Power steering pressure sensor terminal 1
      90 APP sensor terminal 6

    OK or NG

    OK: GO TO 4.

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

  4. CHECK COMPONENTS 

    Check the following.

    OK or NG

    OK: GO TO  7.

    NG: Replace malfunctioning components

  5. CHECK ACCELERATOR PEDAL POSITION SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO  7.

    NG: GO TO 6.

  6. REPLACE ACCELERATOR PEDAL ASSEMBLY 
    1. Replace accelerator pedal position 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