I recently observed that my GPS (new) says that I am going about 10% slower than my speedometer indicates. If this is consistently true with VWs, as the responses I got on the Vortex forum indicate, then it would also follow that the odometer has a similar error and that MPG calculations would be off by a similar factor. The kicker, though, is that if the odometer registers a mile for roughly every .91 miles driven, it follows that the warranties also expire quite a bit before the true mileage is reached. If this is true, what does it mean? Is there some kind of design error? An honest mistake? Outright fraud? Am I the only one concerned, or has this come up before? Any thoughts or opinions welcome.

 

True enough, but if there are calibration errors, they would be consistent throughout that data chain. I'm pretty sure the satellites are calibrated, and the delay is insignificant when traveling at a steady speed. So far as distances are concerned, the GPS is a lot more accurate.