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Home >> Infiniti >> 2006 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0455 To P1217 >> DTC P0643 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: Locating Body Ground Screws
      G04185036Courtesy 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: Identifying Accelerator Pedal Position (APP) Sensor Connector
      G04133065Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between APP sensor terminal 7 and ground with CONSULT-II or tester.

      Voltage: Approximately 5V 

    OK or NG 

    1. OK : GO TO  5.
    2. NG : GO TO 3.
      Fig 3: Identifying Voltage Between APP Sensor Terminal 7 And Ground
      G04133066Courtesy 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

    TERMINALS REFERENCE

    ECM terminal Sensor terminal Reference Wiring Diagram
    48 EVAP control system pressure sensor terminal 3 EC-407
    49 Refrigerant pressure sensor terminal 1 EC-631
    68 Power steering pressure sensor terminal 1 EC-449
    90 APP sensor terminal 7 EC-461

    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