Mass Airflow Sensor

Mass airflow sensor is located in main air intake duct. The sensor uses a hot-wire type sensing element. Incoming air passing through the airflow sensor causes the hot wire to cool. As a result, ECM must apply additional current to maintain hot wire at the precalibrated temperature. The ECM measures airflow by monitoring the amount of additional current required to maintain hot wire at the precalibrated temperature.

If MAF sensor output current is outside normal operational range, a MAF sensor fault is indicated. ECM will use throttle position sensor as primary information on driving condition. During this period, ECM will limit engine speed to less than 2000 or 3000 RPM, depending on model. This will inform the driver that the vehicle is driving under fail-safe conditions and needs attention.