Air Flow Meter/Sensor: Description and Operation

Vane Air Flow (VAF) Meter:

PURPOSE
The Vane 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 signal is used by the ECA when making adjustments to air/fuel mixture, ignition timing, and purge flow control, and turbo boost pressure.

LOCATION
Engine compartment, mounted between air cleaner and throttle body.

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

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 a vane air temperature (VAT) sensor which monitors and relays inlet air temperature to the ECA.