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Home >> Infiniti >> 2005 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P1229: Sensor Power Supply >> 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 Connections
      G02389117Courtesy 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 Harness Connector
      G02389118Courtesy 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  5.
    2. NG: GO TO 3.
    Fig 3: Checking Voltage Between APP Sensor Terminal 6 & Ground
    G02389119Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK SENSOR POWER SUPPLY CIRCUITS 

    Check harness for short to power and short to ground, between the following terminals

    SENSOR POWER SUPPLY CIRCUITS

    ECM terminal Sensor terminal Reference Wiring Diagram
    48 EVAP control system pressure sensor terminal 3 WIRING DIAGRAM 
    49 Refrigerant pressure sensor terminal 1 ASCD INDICATOR 
    68 Power steering pressure sensor terminal 1 WIRING DIAGRAM 
    90 APP sensor terminal 7 WIRING DIAGRAM 

    OK or NG 

    1. OK: GO TO 4.
    2. NG: Repair short to ground or short to power in harness or connectors.
  4. CHECK COMPONENTS 

    Check the following.

    OK or NG 

    1. OK: GO TO 7.
    2. NG: Replace malfunctioning components.
  5. CHECK ACCELERATOR PEDAL POSITION SENSOR 

    Refer to "COMPONENT INSPECTION "

    OK or NG 

    1. OK: GO TO  7.
    2. 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 ".
      1. : INSPECTION END 
  7. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT "

    1. : INSPECTION END