Mass Airflow (MAF) Sensor

MAF sensor uses hot film type sensing element. Hot wire/film is heated to a precalibrated temperature by ECM. Incoming air passing through MAF sensor causes hot wire/film to cool, resulting in the need for ECM to apply additional current to maintain precalibrated temperature. ECM measures airflow by monitoring change in required current supplied to hot wire/film.

If MAF sensor output current is outside of normal operational range, ECM senses a MAF sensor malfunction. ECM will then take driving condition information from throttle position sensor. During this period, ECM limits engine speed to alert driver that vehicle is operating under fail-safe conditions and needs attention.