I have a 00 A6, I purchased back in February I love the drive of the car but there are things that are driving me bonkers.
I took it to a place that checks ur car for free and these are the codes he gave me. HELP!

17087 - brake light switch - F, electrical problem in circuit (P0703) error occurs intermittent
16955 brake light sweitch -F no a plausible signal (P0571) error occurs intermittent

16805 warm up catalyst efficiency (bank 1) below limit (P0421)
16815 warm up catalyst efficiency (bank 2) below limit (P0431)

HELP!!!!!!! HELP!!!!!!!
How serious r these things and should I sell this car? Or get these things fixed?
Are these repairs that I can do myself or another shop or should I take it to the dealer?

Thanks a bunch for ur thoughts and expertise!

__________________
LCD

The fault with the brake light switch will be a simple replacment of the brake light switch and clear the fault memory.
The fault with the catalyst will proberly mean replacment but before doing so it will best to take it to an Audi dealer so they can run proper diagnostics on the car.

Audi scientist