AUY TDI Error Code 17664: Causes & Fixes

Hello,
I'm also struggling with unsatisfactory performance (but really only in the upper range). Checking the error codes reveals 17964 (which is related to the pressure difference). The bellows are intact, so everything seems to be pointing towards that strange solenoid valve.
How can I check this without a VAG tester, and how can I check it with one? Could the mass airflow sensor (MAF) also be related to this?

Greetings.

Hi.

Okay, let's start by doing a test run with data logging of the boost pressure and air mass.
While a voltage difference may indicate a problem with the charging system, the issue could also be located within the charger itself, such as a stuck voltage regulator.