I had this also on my week old T8 with 1.250 km on the odometer... Went to the dealer, he brought it in to the country Volvo importer/dealer. They flew in a couple of swedish Volvo engineers that investigated and drove my car for a week and for 350km, then returned it without finding the exact cause but with a few cables and plugs replaced and a couple of software updates. At least the error message went away and stayed away until now. Now I'm still waiting for Volvo to compensate me for being one of their T8 beta testers (i like the leather travel bag) but i'm happy i got my beautiful car back !
Well, my car is in the dealership in Tulsa and they are not quite sure what's causing the issue. To boot, the brake rotors are in need of being replaced. I figured there would potentially be issues; but it's a bit ridiculous that there are this many issues with a $50K+ car.
My wife had been complaining about a squeaking noise from the brakes. Since we had it at the dealership I mentioned it when going over the issues. The technician said they needed to be replaced. He didn't offer the reason as to why. We got the car at the end of August as part of the OSD program.