They also were sued when it showed that the miles and kilometers weren't racking up equally.I think in the 2000's Honda had some off by 8-10% and some owners sued for warranty loss, IIRC, and diminished resale value? 8% is a lot.
It can't "know" the correct speed if the tires were changed. The only way to know the actual speed, once components are changed, is to either adjust for the changes, or use GPS.They know the "correct" speed and that is used for the odometer. They use another doctored value for display as speedometer output. Edit- @Quattro Pete beat me to it.
No one said it would be accurate if you changed overall diameter of the drive wheels unless I am missing something.It can't "know" the correct speed if the tires were changed. The only way to know the actual speed, once components are changed, is to either adjust for the changes, or use GPS.
SAE specifications require speedometers to be accurate -1% / +3%
Can’t speak for Toyota, but all my Mopar’s have been dead on according to GPS and those mobile speed checks. I’d be driven nuts if they weren’t.
Yes. On my Toyota, I can see three different opinions of my speed---1) the "doctored" value prominently displayed on the instrument panel, 2) the number shown by my GPS navigator, and 3) the speed the car's computer considers to be actual speed, which is readable via ScanGauge plugged into the OBD2 port. At ~60 mph, the instrument panel shows about 1.5 mph above GPS speed, on average, with the present tires. Speed from the OBD2 is roughly midway between the others. Odometer shows about 1% high.They know the "correct" speed and that is used for the odometer. They use another doctored value for display as speedometer output. ...