Mass Airflow (MAF) Sensor

A hot-wire air mass sensor is used to measure airflow into engine. Sensor is attached to air filter housing. The hot wire in sensor is kept at 356°F (180°C) above air temperature.

As airflow increases, wire is cooled and resistance of sensor changes. The resulting current change is converted to a voltage signal, and is used by ECM to calculate the volume of air taken in. See Figure .

If a fault develops with mass airflow sensor signal, signal from throttle valve potentiometer will be substituted for driveability.