If the Mercedes Sprinter van gives you trouble in trying to resolve all the T21 issues. You can get MAF sensor replaced and reset Adaptations with MB Star diagnostic system (SD Connect C4 or C5).
If you know how to do a Quick Test and get to Common Rail in DAS, than following steps down below on how to reset the adaptations of the MAF sensor
Menu path: Quick Test \ Common Rail \ Control unit adaptations \ Initialization after component replacement \ Hot film mass air flow sensor \ Resetting the adaptation values & Resetting the wear values of component ‘Hot film mass air flow sensor.
The Printout steps are from DAS diagnostics of a Mercedes 2013 Sprinter NCV3, but the steps are very similar.
Quick Test
Common Rail
Initialization after component replacement
Hot film
Resetting the adaptation
The air adaptation reset function wasnt added until somewhere around 2015. Early versions of das won’t have it.
