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Home >> Infiniti >> 2024 >> QX80 Premium Select, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (2 Of 2) >> Component /Circuit Diagnosis >> Mass Air Flow Sensor >> Component Inspection
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Component Inspection

  1. CHECK MASS AIR FLOW SENSOR-I SYMBOL
    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Start engine and warm it up to normal operating temperature.
    4. Connect CONSULT and select "DATA MONITOR" mode.
    5. Select "MAS A/F SE-B1", and check the indication.
      Monitor item Condition Indication (V)
      MAS A/F SE-B1 Ignition switch ON (Engine stopped.) Approx. 0.4
      Idle (Engine is warmed-up to normal operating temperature.) 0.7 - 1.2
      2, 500 rpm (Engine is warmed-up to normal operating temperature.) 1.4 - 1.9
      Idle to about 4, 000 rpm 0.7 - 1.2 to Approx. 2.4 *

      * : Check for linear voltage rise in response to engine being increased to about 4, 000 rpm.

    SYMBOL WITHOUT CONSULT

    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Start engine and warm it up to normal operating temperature.
    4. Check the voltage between ECM harness connector terminals under the following conditions.
      ECM Condition Voltage (V)
      Connector + -
      Terminal Terminal
      F91 37
      [MAF sensor signal]      		 42 Ignition switch ON (Engine stopped.) Approx. 0.4
      Idle (Engine is warmed-up to normal operating temperature.) 0.7 - 1.2
      2, 500 rpm (Engine is warmed-up to normal operating temperature.) 1.4 - 1.9
      Idle to about 4, 000 rpm 0.7 - 1.2 to Approx. 2.4 *

      * : Check for linear voltage rise in response to engine being increased to about 4, 000 rpm.

    Is the inspection result normal?

    YES>>

    INSPECTION END

    NO>>

    GO TO 2.

  2. CHECK FOR THE CAUSE OF UNEVEN AIR FLOW THROUGH MASS AIR FLOW SENSOR 
    1. Turn ignition switch OFF.
    2. Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
      • Crushed air ducts
      • Malfunctioning seal of air cleaner element
      • Uneven dirt of air cleaner element
      • Intake valve deposits
      • Improper specification of intake air system parts

    Is the inspection result normal?

    YES>>

    GO TO 4.

    NO>>

    GO TO 3.

  3. CHECK MASS AIR FLOW SENSOR-II SYMBOL
    1. Repair or replace malfunctioning part.
    2. Start engine and warm it up to normal operating temperature.
    3. Connect CONSULT and select "DATA MONITOR" mode.
    4. Select "MAS A/F SE-B1", and check the indication.
      Monitor item Condition Indication (V)
      MAS A/F SE-B1 Ignition switch ON (Engine stopped.) Approx. 0.4
      Idle (Engine is warmed-up to normal operating temperature.) 0.7 - 1.2
      2, 500 rpm (Engine is warmed-up to normal operating temperature.) 1.4 - 1.9
      Idle to about 4, 000 rpm 0.7 - 1.2 to Approx. 2.4 *

      * : Check for linear voltage rise in response to engine being increased to about 4, 000 rpm.

    SYMBOL WITHOUT CONSULT

    1. Repair or replace malfunctioning part.
    2. Start engine and warm it up to normal operating temperature.
    3. Check the voltage between ECM harness connector terminals under the following conditions.
      ECM Condition Voltage (V)
      Connector + -
      Terminal Terminal
      F91 37
      [MAF sensor signal]      		 42 Ignition switch ON (Engine stopped.) Approx. 0.4
      Idle (Engine is warmed-up to normal operating temperature.) 0.7 - 1.2
      2, 500 rpm (Engine is warmed-up to normal operating temperature.) 1.4 - 1.9
      Idle to about 4, 000 rpm 0.7 - 1.2 to Approx. 2.4 *

      * : Check for linear voltage rise in response to engine being increased to about 4, 000 rpm.

    Is the inspection result normal?

    YES>>

    INSPECTION END

    NO>>

    GO TO 4.

  4. CHECK MASS AIR FLOW SENSOR-III SYMBOL
    1. Turn ignition switch OFF.
    2. Disconnect mass air flow sensor harness connector and reconnect it again.
    3. Start engine and warm it up to normal operating temperature.
    4. Connect CONSULT and select "DATA MONITOR" mode.
    5. Select "MAS A/F SE-B1", and check the indication.
      Monitor item Condition Indication (V)
      MAS A/F SE-B1 Ignition switch ON (Engine stopped.) Approx. 0.4
      Idle (Engine is warmed-up to normal operating temperature.) 0.7 - 1.2
      2, 500 rpm (Engine is warmed-up to normal operating temperature.) 1.4 - 1.9
      Idle to about 4, 000 rpm 0.7 - 1.2 to Approx. 2.4 *

      * : Check for linear voltage rise in response to engine being increased to about 4, 000 rpm.

    SYMBOL WITHOUT CONSULT

    1. Turn ignition switch OFF.
    2. Disconnect mass air flow sensor harness connector and reconnect it again.
    3. Start engine and warm it up to normal operating temperature.
    4. Check the voltage between ECM harness connector terminals under the following conditions.
      ECM Condition Voltage (V)
      Connector + -
      Terminal Terminal
      F91 37
      [MAF sensor signal]      		 42 Ignition switch ON (Engine stopped.) Approx. 0.4
      Idle (Engine is warmed-up to normal operating temperature.) 0.7 - 1.2
      2, 500 rpm (Engine is warmed-up to normal operating temperature.) 1.4 - 1.9
      Idle to about 4, 000 rpm 0.7 - 1.2 to Approx. 2.4 *

      * : Check for linear voltage rise in response to engine being increased to about 4, 000 rpm.

    Is the inspection result normal?

    YES>>

    INSPECTION END

    NO>>

    Clean or replace malfunctioning mass air flow sensor. Refer to AIR CLEANER AND AIR DUCT : Removal and Installation .

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