" it's not a bad idea to have them read at Autozone before bringing it to the dealer."

Being a dealer tech, I can tell you that IF you're planning to go there anyway, there's no need to waste time stopping at a parts store first. No dealer tech (or tech anywhere) will go by another places fault codes for diagnostic purposes. Any tech will read their own fault codes first and Volvos fault codes aren't the same as a generic scan tool.

If one goes to Autozone, gets a code read, buys that part and gets lucky, fine but it doesn't always go that smoothly and one might also waste money if it's not that part.