Air Flow Meter/Sensor: Description and Operation

Mass Air Flow Sensor

Mass Air Flow (MAF) Sensor:

Note: Moisture or other contamination of the MAF sensing element can cause incorrect air flow input to the PCM resulting in EGR or VGT DTC's.

The mass air flow (MAF) sensor provides an analog voltage signal to the PCM proportional to the intake air mass. The MAF sensor utilizes a hot wire sensing element to measure the amount of air entering the engine. The hot wire is maintained at 200°C (392°F) above ambient temperature. Air passing over the hot wire cools the wire. The current required to maintain the temperature of the hot wire is proportional to the air mass flow. The MAF signal is used for exhaust pressure calculator and exhaust gas recirculation (EGR) diagnostics.