A4 B6 2.0 96kw O2 problem

Hello!
I own a A4 2.0 96kw (petrol) and my check engine light is on. Diagnostics discovered 3 fault codes: P0420- Catalytic converter system (bank 1) Inadequate effect.
P1136- Additive mixture adaptation for air (Bank 1) System too lean
P1479- Brake vacuum system. Mechanical fault
I discovered 2 not good looking vacuum hoses and replaced them. But the engine light came back on and the fault codes were the same. Now I replaced my PVC valve. I think the engine light will appear soon. We discovered that the O2 voltage sensor showed an average of 1.56. Pretty sure it should be somewhere around 1 or less. My car was in park but the O2 graphic went up, then was stable for couple of seconds and then went up for a sec again. Any ideas about discovering the problem?

Please post a full unedited edited VCDS Auto-Scan so we can see the fault codes and how your A4 is configured.

Unfortunately I do not own the equipment. I just had my car checked and these fault codes are what they gave me. So basically the oil goes to the air system somehow and the overall average O2 is too high. I wish I could provide some more information.

You can by buying a system and posting your first auto-scan!

https://store.ross-tech.com/shop/cat/VCDS

I guess engine code is ALT. Check intake, PCV and vacuum systems. They have a lot of parts that use to fail when not new anymore. And all three systems are connected.
We have some forum members (and owners of VCDS, of course) in Estonia, You can try to ask them for help.

DID SOMEONE SAY GUESS LIKE A DIAGNOSTIC OF CHANCE?