Mass Airflow (MAF) Sensor

MAF sensor measures flow of air entering the engine. This measurement of airflow is a reflection of engine load (throttle opening). The sensing element (hot wire) is a thin platinum wire wound on a ceramic bobbin and coated with glass.

The hot wire is maintained at 392°F (200°C) greater than a downstream cold (ambient) temperature wire. As airflow through the airflow sensor increases, the temperature of the hot wire drops. The PCM must then increase current flow through the hot wire to maintain the desired temperature. This increased current requirement is a direct reflection of airflow volume. The PCM uses this information to control fuel delivery.