The vehicle is capable of setting the time via GPS, but it is not enabled in every market. YOu can set that up while coding, if it isn't, and I'm pretty sure it's an option in BimmerCode. My new X5 sets its internal clock automatically, or at least it switched itself to the proper DST when the change occurred. I've not really checked to see how accurate it is down to the second, though.
Back over 30-years ago, I had an electric clock that I added to my motorcycle, and found that it was extremely accurate where it was to the second after about 6-months compared to WWV (no GPS back then!). So, it's possible to make a quartz clock quite accurate without augmentation. One would think that the cpu governing the update on the internal clock could be quite accurate, but that doesn't always seem to be true! Was in a Sharper Image store years ago when they still had retail locations, and was browsing the clocks that were supposed to automatically set themselves from WWV and they were all different. I have one like that in my shower that for over a month, has not detected that the clock should be shifted...sometimes, it works right, sometimes it doesn't, but it was lots cheaper than the i3!
