eem03

I have a 03 gmc z71 that my 16yr. son drives with the same problem. It has a mind of it's own. I was driving it this week and all of a sudden it started flashing language options. We have reset the language to english with the trip button per instructions above, but it started flashing three languages option shortly afterwards. After 10-15 minutes, I looked at it and it was in French (I think). I have disconnected battery hoping it would reset but on vale. Today when I attempted to reset it again, the odometer/mileage reading did not display. It only flashed language options and I understand it can only be reset while displaying the mileage. What's involved in a re-program? Any help would appreciated. Ed