#1
Don't panic and start fixing things that aren't broken and breaking things that are good. This problem is not uncommon and happens for a variety of reasons including a lower battery voltage after the car has been in the shop for a while, or a simple burned out brake light.
Rather than re-post my favorites from the search, I'll let you take your pick:
https://www.google.com/search?client=firefox-b-1-d&q=abs+and+psm+after+sitting+porsche
I had the steering angle sensor code on my '04, and it simply reset and tested good the next time I took it out.