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Home >> Infiniti >> 2019 >> QX50 Essential, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC/Circuit Diagnosis) (2 Of 12) >> DTC/Circuit Diagnosis >> DTC P0101: MAF Sensor >> Component Inspection (Mass Air Flow Sensor)
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Component Inspection (Mass Air Flow Sensor)

  1. CHECK MASS AIR FLOW (MAF) SENSOR-1 

    SYMBOL With CONSULT

    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Start the engine and warm it up to normal operating temperature.
    4. Select "MASS AIR FLOW SENSOR (Hz) B1" in "DATE MONITOR" mode of "ENGINE" using CONSULT and check the indication under the following condition.

      Monitor item

      Condition

      Indication

      MASS AIR FLOW SENSOR (Hz) B1

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      Idle (Engine is warmed-up to normal operating temperature.)

      5, 000- 5, 400 Hz

      Engine is warmed-up to normal operating temperature.

      5, 700- 6, 300 Hz

      Idle to about 4, 000 rpm

      6, 300- 7, 100 Hz*

      *: Check for linear frequency rise in response to increase of engine speed.

    SYMBOL Without CONSULT

    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Start the engine and warm it up to normal operating temperature.
    4. Check the frequency between ECM harness connector terminals under the following conditions.

      ECM

      Condition

      Frequency

      Connector

      +

      -

      Terminal

      F51

      26

      23

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      Idle (Engine is warmed-up to normal operating temperature.)

      5, 000- 5, 400 Hz

      Engine is warmed-up to normal operating temperature.

      5, 700- 6, 300 Hz

      Idle to about 4, 000 rpm

      6, 300- 7, 100 Hz*

      *: Check for linear frequency rise in response to increase of engine speed.

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    GO TO 2.

  2. CHECK FOR THE CAUSE OF UNEVEN AIR FLOW THROUGH INTAKE AIR DUCT 
    1. Turn ignition switch OFF.
    2. Check for the cause of uneven air flow through intake air duct. Refer to the following.
      • Crushed air ducts
      • Malfunctioning seal of air cleaner element
      • Uneven dirt like leaves or insects of air cleaner element
      • Intake valve deposit
      • Improper specification of intake air system parts

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    GO TO 3.

  3. CHECK MAF SENSOR-2 

    SYMBOL With CONSULT

    1. Repair malfunctioning part.
    2. Start the engine and warm it up to normal operating temperature.
    3. Select "MASS AIR FLOW SENSOR (Hz) B1" in "DATE MONITOR" mode of "ENGINE" using CONSULT and check the indication under the following condition.

      Monitor item

      Condition

      Indication

      MASS AIR FLOW SENSOR (Hz) B1

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      Idle (Engine is warmed-up to normal operating temperature.)

      5, 000- 5, 400 Hz

      Engine is warmed-up to normal operating temperature.

      5, 700- 6, 300 Hz

      Idle to about 4, 000 rpm

      6, 300- 7, 100 Hz*

      *: Check for linear frequency rise in response to increase of engine speed.

    SYMBOL Without CONSULT

    1. Repair malfunctioning part.
    2. Start the engine and warm it up to normal operating temperature.
    3. Check the frequency between ECM harness connector terminals under the following conditions.

      ECM

      Condition

      Frequency

      Connector

      +

      -

      Terminal

      F51

      26

      23

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      Idle (Engine is warmed-up to normal operating temperature.)

      5, 000- 5, 400 Hz

      Engine is warmed-up to normal operating temperature.

      5, 700- 6, 300 Hz

      Idle to about 4, 000 rpm

      6, 300- 7, 100 Hz*

      *: Check for linear frequency rise in response to increase of engine speed.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    GO TO 4.

  4. CHECK MAF SENSOR-3 

    SYMBOL With CONSULT

    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Start the engine and warm it up to normal operating temperature.
    4. Select "MASS AIR FLOW SENSOR (Hz) B1" in "DATE MONITOR" mode of "ENGINE" using CONSULT and check the indication under the following condition.

      Monitor item

      Condition

      Indication

      MASS AIR FLOW SENSOR (Hz) B1

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      Idle (Engine is warmed-up to normal operating temperature.)

      5, 000- 5, 400 Hz

      Engine is warmed-up to normal operating temperature.

      5, 700- 6, 300 Hz

      Idle to about 4, 000 rpm

      6, 300- 7, 100 Hz*

      *: Check for linear frequency rise in response to increase of engine speed.

    SYMBOL Without CONSULT

    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Start the engine and warm it up to normal operating temperature.
    4. Check the frequency between ECM harness connector terminals under the following conditions.

      ECM

      Condition

      Frequency

      Connector

      +

      -

      Terminal

      F51

      26

      23

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      Idle (Engine is warmed-up to normal operating temperature.)

      5, 000- 5, 400 Hz

      Engine is warmed-up to normal operating temperature.

      5, 700- 6, 300 Hz

      Idle to about 4, 000 rpm

      6, 300- 7, 100 Hz*

      *: Check for linear frequency rise in response to increase of engine speed.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Replace MAF sensor. Refer to Exploded View .

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