Yup sounds like an ABS Controller problem.

As others have stated these cars are overly complex in the electronics dept (16 seperate computers talking over a CAN lo/hi speed network).

This model is the first Volvo have tried all this new technology in (Complex CAN networks, transverse mounted engine+autobox etc); in other words the earlier S80's were in my opinion essentially mass produced test vehicles; hence all the nightmares people have suffered with the gearbox, electronics etc.

This may have improved in later models but I suggest you do what im doing; get rid of the car asap or be prepared for some serious spending if something fails out of warranty (more a question of WHEN than IF really IMO).

Dont get me wrong these are brilliant to drive etc. but full of potentially expensive gremlins.