The mass flow sensor measures the air that flows through the intake manifold into the combustion engine. It can usually be found in the intake manifold, behind the air filter, and in front of the throttle valve.

If the sensor measures the air pressure in the intake manifold, it is denoted by the abbreviation MAP - Manifold Air Pressure. On the other hand, if it measures the mass of the consumed air, it is denoted by the abbreviation MAF - Mass Air Flow.