what is a maf
(November 2009). A mass airflow sensor. A mass (air) flow sensor (MAF) is used to find out the mass flowrate of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine.he VAF (volume air flow) sensor measures the air flow into the engine with a spring-loaded air vane (flap/door) attached to a variable resistor (potentiometer).