Air mass deviations in the event of sooting
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.
In the event of sooting in the intake area, the measured air mass will deviate more from the calculated air mass as the engine speed increases (measured air mass too low).