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Home >> Nissan-Datsun >> 2004 >> Sentra Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - QG18DE >> DTC P0101: MAF Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. INSPECTION START 

    Which malfunction (A or B) is duplicated?

    A or B 

    1. A: GO TO  3.
    2. B: GO TO 2.
  2. CHECK INTAKE AIR LEAK 

    Check the following for connections.

    • Air duct
    • Vacuum hoses
    • Intake air passage between air duct and collector

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Reconnect the parts.
  3. RETIGHTEN GROUND SCREWS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten engine ground screws.
    1. : GO TO 4.
    Fig 1: Loosening And Retightening Engine Ground Screws
    G00774816Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK MAF SENSOR POWER SUPPLY CIRCUIT 
    1. Disconnect mass air flow sensor harness connector.
    2. Turn ignition switch ON.
      Fig 2: Disconnecting Mass Air Flow Sensor Harness Connector
      G00774817Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between MAF sensor terminals 2, 4 and ground with CONSULT-II or tester.
      Fig 3: Terminal Voltage Chart
      G00774818Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 4: Checking Voltage Between MAF Sensor Terminals 2, 4 And Ground With CONSULT-II Or Tester
      G00774819Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO  6.
    2. NG: GO TO 5.
  5. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness for open or short between ECM relay and mass air flow sensor
    • Harness for open or short between mass air flow sensor and ECM
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect TCM harness connector.
    4. Check harness continuity between MAF sensor terminal 3 and ECM terminal 67, TCM terminal 42.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    5. Also check harness for short to ground and short to power.

    OK or NG 

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

    Check the following.

    • Harness for open or short between mass air flow sensor and ECM
    • Harness for open or short between mass air flow sensor and TCM
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  8. CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check harness continuity between MAF sensor terminal 1 and ECM terminal 51.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    2. 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 MASS AIR FLOW SENSOR 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK: GO TO 10
    2. NG: Replace mass air flow sensor.
  10. CHECK INTERMITTENT INCIDENT 

    Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    1. INSPECTION END 
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