This is the button that you press to display either trip mileage or the complete mileage. No matter how or when I push it, it won't display the original mileage. It last did about 4-5 months ago, but not since then. I wonder if disconnecting the battery long enough (3 minutes or so) might help the car to reset itself. I really DON'T want to take it to DEALER SERVICE as it's out of warranty. Any thoughts, anyone???