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Home >> Nissan-Datsun >> 2004 >> Frontier Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Control System - KA24DE >> DTC P0121: TP Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. INSPECTION START 

    Which malfunction A or B is duplicated?

    Fig 1: Inspection chart
    G00857036Courtesy of NISSAN MOTOR CO., U.S.A.

    Type A or B 

    1. Type A : GO TO  4.
    2. Type B : GO TO 2.
  2. ADJUST THROTTLE POSITION SENSOR 
    1. Check the following items. Refer to Basic Inspection .
      Fig 2: Adjust Throttle Position Sensor Chart
      G00857037Courtesy of NISSAN MOTOR CO., U.S.A.
      1. : GO TO 3.
  3. CHECK INTAKE SYSTEM 

    Check the following for connection.

    • Air duct
    • Air cleaner
    • Vacuum hoses
    • Intake air passage between air duct to intake manifold collector

    OK or NG 

    1. OK : GO TO 4.
    2. NG : Reconnect the parts.
  4. RETIGHTEN GROUND SCREWS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten engine ground screws.
      1. : GO TO 5.
      Fig 3: Tightening Engine Ground Screws
      G00857038Courtesy of NISSAN MOTOR CO., U.S.A.
  5. CHECK POWER SUPPLY 
    1. Disconnect throttle position sensor harness connector.
    2. Turn ignition switch ON.
      Fig 4: Disconnecting Throttle Position Sensor Harness Connector
      G00857039Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between terminal 1 and ground with CONSULT-II or tester.

      Voltage : Approximately 5V 

    OK or NG 

    1. OK : GO TO 6.
    2. NG : Repair harness or connectors.
      Fig 5: Checking Voltage Between Terminal And Ground
      G00857040Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Check harness continuity between throttle position sensor terminal 3 and engine ground. Refer to WIRING DIAGRAM .

      Continuity should exist. 

    3. Also check harness for short to power.

    OK or NG 

    1. OK : GO TO  8.
    2. NG : GO TO 7.
  7. DETECT MALFUNCTIONING PART 

    Check harness for open or short between ECM and throttle position sensor.

    1. : Repair open circuit or short to power in harness or connectors.
  8. CHECK INPUT SIGNAL CIRCUIT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 23 and terminal 2. Refer to WIRING DIAGRAM .

      Continuity should exist. 

    3. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK : GO TO 9.
    2. 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 

    1. OK : GO TO 10.
    2. NG : Replace throttle position sensor. To adjust it, perform Basic Inspection .
  10. CHECK MASS AIR FLOW SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 11.
    2. NG : Replace mass air flow sensor.
  11. CHECK CAMSHAFT POSITION SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 12.
    2. NG : Replace distributor assembly with camshaft position sensor.
  12. CHECK FUEL INJECTOR 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 13.
    2. NG : Replace fuel injector.
  13. CHECK INTERMITTENT INCIDENT 

    Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    1. : INSPECTION END. 
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