Check engine light came one. I'm past the 50,000 mile warranty (I am at 54,000). Audi service department gave me codes: P227900 Intake Air System Leak and P218700 System too lean at idle, Bank 1.

I opened hood and noticed a leak noise coming from picture attached. Does anyone know what part this is? Or why it is leaking? Thanks in advance.

 

That is the PCV. They can go bad. About an $80 part and easy to change out.

https://www.ecstuning.com/Audi-B8_A4....0T/ES2707347/

Product Details

From the 2013 model year

The PCV provides a one way exit for gasses built up in the crankcase. Over time, contamination might cause reduced air flow and cracks can occur in the housing. If your car is experiencing a loss of boost pressure or a decrease in performance with a rough idle, this valve might to be blame. This valve sits on the cylinder head valve cover.