My guess would be that one of the computer units failed. A similar thing happened in my FEH a couple of months ago (it was fairly new, I bought it in April '05 and this was just before Thanksgiving), in my case it was the main brake computer, the warnings were "service brakes" and "service 4X4", and the brakes didn't work very well. It was the first very cold morning we'd had this winter. I had it towed to the shop, it took a few days (OK, I guess it was over a week) for them to get the part (it was backordered), get it installed, and the vehicle's been working perfectly since. Just one of those fluke-y things.

Good luck! Let us know how it resolves.