Mass Airflow 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 voltage signal and is used by ECM to calculate the volume of air taken in.

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