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Home >> Nissan-Datsun >> 2005 >> Sentra Base, Automatic >> Repair and Diagnosis >> Engine Performance >> 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 

    A : GO TO  3.

    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 

    • OK : GO TO 3.
    • NG : Reconnect the parts.
  3. RETIGHTEN GROUND SCREWS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten two ground screws on the body. Refer to "GROUND INSPECTION ".
      Fig 1: Locating ECM Ground Screws
      G02449775Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK : GO TO 4.
    • NG : Repair or replace ground connections.
  4. CHECK MAF SENSOR POWER SUPPLY CIRCUIT 
    1. Disconnect mass air flow sensor harness connector.
      Fig 2: Disconnecting Mass Air Flow Sensor Harness Connector
      G02449776Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Turn ignition switch ON.
    3. Check voltage between MAF sensor terminals 2 and ground with CONSULT-II or tester.
      • Voltage : Battery voltage. 
      Fig 3: Checking Voltage Between MAF Sensor Terminals 2 And Ground
      G02449777Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK : GO TO  6.
    • 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
      • : 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 .
      • Continuity should exist. 
    5. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO  8.
    • 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
      • : 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 4 and ECM terminal 51. 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 INTAKE AIR TEMPERATURE SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    • OK : GO TO 10.
    • NG : Replace intake air temperature sensor.
  10. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    • OK : GO TO 11.
    • NG : Replace EVAP control system pressure sensor.
  11. CHECK MASS AIR FLOW SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    • OK : GO TO 12.
    • NG : Replace mass air flow sensor.
  12. CHECK INTERMITTENT INCIDENT 

    Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    • : INSPECTION END 
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