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Home >> Nissan-Datsun >> 2004 >> Pathfinder LE, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> 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 SYSTEM 

    Check the following for connection.

    • Air duct
    • Vacuum hoses
    • Intake air passage between air duct and intake manifold 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.
      Fig 1: Loosening Engine Ground Screws
      G00334436Courtesy of NISSAN MOTOR CO., U.S.A.
      1. GO TO 4.
  4. CHECK MAF SENSOR POWER SUPPLY CIRCUIT 
    1. Disconnect mass air flow (MAF) sensor harness connector.
      Fig 2: Disconnecting Mass Air Flow (MAF) Sensor Harness Connector
      G00334437Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Turn ignition switch "ON".
    3. Check voltage between MAF sensor terminal 2 and ground with CONSULT-II or tester.
      Fig 3: Checking Voltage Between MAF Sensor Terminal 2 And Ground
      G00334438Courtesy of NISSAN MOTOR CO., U.S.A.

      Voltage: Battery voltage 

    OK or NG 

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

    Check the following.

    • Harness connector E1, M1
    • Harness connector M32, F23
    • 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 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 

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

    Check the following.

    • Harness connectors F22, M33
    • Joint connector
    • 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 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 

    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 
    1. Reconnect harness connectors disconnected.
    2. Start engine and warm it up to normal operating temperature.
    3. Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.
      Fig 4: Checking Voltage Between ECM Terminal 51 And Ground
      G00334439Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 5: Voltage Chart
      G00334440Courtesy of NISSAN MOTOR CO., U.S.A.
    4. If the voltage is out of specification, disconnect MAF sensor harness connector and connect it again. Then repeat above check.

    OK or NG 

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

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  " .

    1. INSPECTION END 
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