his problem will not shut the car down because it's not a Safety issue like the ABS Brake Module. As you said, the car runs fine, just the annoying messages. The computer thinks there is a problem for optimum performance, but again it won't hurt the engine and based on your description, it's not about to go out as you are concerned with. Probably could go a year. What you are looking at is a good indication of when you will want to get the service done, when it accelerates poorly or changes performance significantly. Try some STP in the gas tank if you don't want to fool with the service. I would think Canada would cost less.

The service to fix this is to have the Throttle module cleaned or better replaced and should also include replacing the (MAF) Mass Air Flow Sensor located at the Air Cleaner assembly. It's not cheap which is why so many S80s out there have the annoying warning lights off and on.

GR