[swagetti_yolonese]

I have this error:

25D400 - Exhaust backpressure sensor before turbocharger, signal too high

We have replaced the fuel pipe and sensors already and cleaned the computer and wires.

The mechanic says that we should try replacing the turbocharger next.
I don't like the lack of confidence here. He is not sure if that is the problem (this is the best mechanic in the city).

What should I do?
I saw some other threads on this, and everybody managed to fix it by cleaning the computer. I couldn't.