Buy a scanguage; it will calculate the true speed for you. There are other reasons to buy it, too. So, umm...buy it anywayI want to put 315/70/17 on the FJ however the tire calculator indiates a 5mph diff in the speedometer. Can this be corrected and if how? Thx for the info.
You have the x-gauge one, right? If so, you can change speed calibration as a percentage of the ECU speed. Looking at the instructions, go to MORE>SETUP>SPEED and change the percentage to match actual speed.Podex do you mean the new firmware update? Or does mine do something I didn't know it did?