Techn. Problem with my V8

Have this problem and the workshop seems to have even less idea than I do..

1. So, the on-board computer has signaled that my front brakes need to be renewed. The workshop then changed the windows, coverings and sensors. So far so good, only the on-board computer continues to report the error... ???

2. If my fat one is warm, he refuses to serve and just doesn't want to start. Error protocol says: Temperature sensor. So the workshop changed both of them. Problem is, it doesn't start when it's warm... ???

Small additional info: the thickness runs in the emergency program. I don't know what it's all about.

Would be really great if someone could give a tip to my qualified VAG workshop.

Thank you
Your Jürgen