Mass Airflow Meter

Two types of airflow meters are used. The first is a potentiometer type which uses a swinging door to measure the rate of air flow. The amount of air door movement is translated to the ECU via voltage signals. The second type measures airflow by monitoring the change of electrical resistance in the circuit that dissipates heat from the wire located in path of incoming air. The more incoming air entering through the airflow meter, the more heat removed from the hot wire. The more heat removed from hot wire the less resistance present in that circuit. The ECU evaluates the air flow rate through this change in resistance.