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Home >> Nissan-Datsun >> 2021 >> Sentra S >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (2 Of 2) >> Components/Circuit Diagnosis >> Mass Air Flow Sensor >> Component Inspection
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Component Inspection

  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)" 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)

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      1500 RPM (Engine is warmed-up normal operating temperature)

      5, 400 - 5, 900 Hz

      2500 RPM (Engine is warmed-up normal operating temperature)

      5, 900 - 6, 400 Hz

      4000 RPM (Engine is warmed-up normal operating temperature)

      6, 400 - 7, 200 Hz

    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

      F24

      26

      23

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      1500 RPM (Engine is warmed-up normal operating temperature)

      5, 400 - 5, 900 Hz

      2500 RPM (Engine is warmed-up normal operating temperature)

      5, 900 - 6, 400 Hz

      4000 RPM (Engine is warmed-up normal operating temperature)

      6, 400 - 7, 200 Hz

    Is the inspection result normal?

    YES

    INSPECTION END

    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)" 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)

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      1500 RPM (Engine is warmed-up normal operating temperature)

      5, 400 - 5, 900 Hz

      2500 RPM (Engine is warmed-up normal operating temperature)

      5, 900 - 6, 400 Hz

      4000 RPM (Engine is warmed-up normal operating temperature)

      6, 400 - 7, 200 Hz

    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

      F24

      26

      23

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      1500 RPM (Engine is warmed-up normal operating temperature)

      5, 400 - 5, 900 Hz

      2500 RPM (Engine is warmed-up normal operating temperature)

      5, 900 - 6, 400 Hz

      4000 RPM (Engine is warmed-up normal operating temperature)

      6, 400 - 7, 200 Hz

    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)" 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)

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      1500 RPM (Engine is warmed-up normal operating temperature)

      5, 400 - 5, 900 Hz

      2500 RPM (Engine is warmed-up normal operating temperature)

      5, 900 - 6, 400 Hz

      4000 RPM (Engine is warmed-up normal operating temperature)

      6, 400 - 7, 200 Hz

    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

      F24

      26

      23

      Ignition switch ON (Engine stopped.)

      Approx. 3, 700 Hz

      1500 RPM (Engine is warmed-up normal operating temperature)

      5, 400 - 5, 900 Hz

      2500 RPM (Engine is warmed-up normal operating temperature)

      5, 900 - 6, 400 Hz

      4000 RPM (Engine is warmed-up normal operating temperature)

      6, 400 - 7, 200 Hz

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Replace MAF sensor. Refer to Exploded View .

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