How to diagnose a faulty turbocharger in Audi A6?

I suspect that my Audi A6 may have a faulty turbocharger, but how can I confirm it? Are there any specific tests or symptoms I should look out for in order to diagnose the issue?

Firstly, you can check for any unusual noises coming from the turbocharger. This could indicate a damaged or worn-out bearing. Additionally, you can have a mechanic perform a boost pressure test to determine if there are any issues with the turbocharger's efficiency. Finally, check for any visible signs of wear or damage on the turbocharger itself, such as oil leaks or cracks.