Vane Airflow Meter (VAF)

The VAF is mounted in the air inlet, between air cleaner and throttle body. It measures the volume of air entering into the engine by monitoring the position of a movable door. A potentiometer, attached to VAF door, signals door position to the ECA. The ECA translates door position to volume of air entering the engine.

The VAF also contains a temperature sensor. The temperature of air entering the engine is monitored and transmitted to the ECA. The ECA is programmed to compute airflow and air temperature, so fuel flow can be adjusted to obtain optimum air/fuel mixture. The VAF also contains a fuel pump switching circuit to cut fuel pump operation when the engine is off.

On 1.8L models, this signal affects air/fuel ratio, injector timing, ignition timing and canister purge flow. On 2.2L models, this signal affects air/fuel ratio ignition timing (turbo), boost pressure (turbo) and canister purge flow.