I recently purchased a 2016 Edge Titanium, that originally entered service in Canada, to replace the 1999 Taurus SE that I drove into the ground. Curious about the on-board GPS capabilities, I decided to compare the distance the tripometer registered versus actual distance as measured by a handheld GPS and my iPhone.

On two different 500+ mile trips, the Edge registered about 98.65% of the actual mileage. This also seems to extend to the speedometer, per comparisons to speed guns.

I know that per federal laws, a car only has to be within 5%, and being a bit slow works in my favor. I also know this could come down to the gear ratio, over-or-underinflated or non-standard tires, etc. My question is this: is there any reason to try to improve the odometer etc. accuracy while it’s still under warranty? Any easy way to do it if so? Is it even legal to “update” the odometer?