O2 Sensor, changed lamda, still "check engine"

[Rs4b8AA]

Hello!

Thanks for this forum.

I have read and searched a lot on this topic but can not find an answer. My engine light is yellow even though I have changed the lambda, still gives an error code on p223700.

Any ideas?

Thanks in advance!

[Rs4b8AA]

For the future, Audi has it to solv the problem, seems to be the control unit. (ECU)

[Rusty Racer]

Sounds expensive!