Air Flow Meter/Sensor: Description and Operation

Volume Air Flow (VAF) Meter:

PURPOSE
The Volume Air Flow (VAF) meter measures air flowing into the engine by means of a signal generated by a movable vane connected to a potentiometer. The input signal is used by the Powertrain Control Module (PCM) when making adjustments to air/fuel mixture, ignition timing, and purge flow control.

OPERATION
As air flows through the VAF meter, the movable vane and potentiometer change positions and provide an air flow input to the PCM.

CONSTRUCTION
The VAF meter contains a potentiometer connected to a movable vane. Inside the VAF meter is a fuel pump switch providing a ground for the fuel pump circuit after the engine has started. The meter also contains an Intake Air Temperature (IAT) sensor which monitors and relays inlet air temperature to the PCM.