As specified for all newer TDI engines (especially the PD), check your airbox for the correct part number. This is the "suffix A" air filter which has an extra layer of foam at the bottom, effectively acting as a prefilter. This extra layer takes the place of the snorkel/snowscreen which was present on the older cars.

While installing, be sure to verify that the airbox cover is properly seated and sealed. Applicable for all A4 ALH models including PDs.