Check Valve With Vacuum Line In Engine Compartment, Removing And Installing, 3.0L TFSI Engine: Notes
WARNING: This page is about a different car, the 2021 Audi S4 and 2021 Audi A4 Quattro. However, it is still accessible from the selected car via links, so may be relevant.
The check valve is integrated in the vacuum line and cannot be replaced separately.