Fair point, but fixing the dash odometer is fairly easy but fixing it also in all the other locations where the info is stored is not and less likely to be done, That is the information I have gleaned from limited research so far anyway, plus I will need a system for checking fault codes and other issues so it may as well include this function. I just found a video as it happens where this process is done and is part of a series OBD2 scanners for complete beginners. If anyone is interested this is the title of the youtube video you could search on "OBD2 basic Part 1: Which OBD2 scanner to buy?" In the video he appears to be sat in a Toyota while he does the rollback check using the 'Thinkdiag2' scan tool. Video position 2.25 ????