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Home >> Infiniti >> 2004 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> DTC P0122, P0123: TP Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten ground three screws on the body.
      Fig 1: Locating Body Ground
      G02691252Courtesy 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 THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-I 
    1. Disconnect electric throttle control actuator harness connector.
    2. Turn ignition switch ON.
      Fig 2: Locating Electric Throttle Control Actuator And Throttle Control Motor Harness Connector
      G02691253Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between electric throttle control actuator terminal 2 and ground with CONSULT-II or tester.

      Voltage: Approximately 5V 

    OK or NG

    OK: GO TO  7.

    NG: GO TO 3.

    Fig 3: Checking Voltage Between Electric Throttle Control Actuator Terminal 2 & Ground
    G02691254Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-II 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between electric throttle control actuator terminal 2 and ECM terminal 47.

      Refer to Wiring Diagram.

      Continuity should exist. 

    OK or NG

    OK: GO TO 4.

    NG: Repair or replace open circuit.

  4. CHECK THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-II 

    Check the following.

    • Harness for short to power and short to ground, between the following terminals.
    CHECK THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-II

    ECM terminal Sensor terminal
    47 Electric throttle control actuator terminal 2
    91 APP sensor terminal 7

    OK or NG

    OK: GO TO 5.

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

  5. CHECK ACCELERATOR PEDAL POSITION SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO  11.

    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 THROTTLE POSITION SENSOR 2 GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between electric throttle control actuator terminal 4 and ECM terminal 66.

      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 8.

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

  8. CHECK THROTTLE POSITION SENSOR 2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check harness continuity between ECM terminal 69 and electric throttle control actuator terminal 3.

      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 9.

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

  9. CHECK THROTTLE POSITION SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG

    OK: GO TO  11.

    NG: GO TO 10.

  10. REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR 
    1. Replace the electric throttle control actuator.
    2. Perform THROTTLE VALVE CLOSED POSITION LEARNING .
    3. Perform IDLE AIR VOLUME LEARNING .

      : INSPECTION END 

  11. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    : INSPECTION END 

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