Nav version upgrade screwing with MPG?
 

A while back i upgraded my nav to v27. In the process, of messing around with it, I down graded and upgraded again. This put it into euro? mode, which got rid of the "yes i agree" legal BS, but i think it did more than that.

Ever since then, my gas milage has been way off, reporting like 35mpg, but when i do the math, it's closer to 29. From what I can tell, it's measuring mpg using UK gallons instead of US gallons. Does this make sense? Adjusted, the MPG is almost exacrly what i'm actually getting. Is there any way to change it back? Do i need to take it to the dealer and have it coded to the US again, and if i do, will the "I agree" BS come back?

Yes you have to take it back to the dealer to get it recoded into the U.S. mode. And you are also right about your X5 being in imperial gallons.

In U.S. mode the accept screen will come back... you have our lovely lawsuits to thank for that. But with v. 27 the accept screen disappears in 8 seconds. Which means that by the time I back my X3 out of the garage, and set it in D - the accept screen is gone...

I dont want to see that screen at all. Maybe if it was only for NAV mode(like other cars), but it's for everything! I'll just trick people to thinking my car gets hybrid like mileage.

Check out this post. I fixed the MPG problem in my car by pulling the fuses for the OBC. These are E38 fuses, but try pulling the corresponding X5 fuses.

http://www.bimmerboard.com/forums/posts/174341/

Intresting. I'll have to give that a try. I actually have an E46, so i'll have to figure out which are the right fuses. Thanks!