Cannot set speedo with EFI

[gneal02]

Went to a shorter tire and cannot adjust tire size. It saves it in there but nothing changes when I drive it. It seems to be stuck on the tire size that I had in with my old Smarty. No matter the number I put in, it reads 2.5 mph faster than I'm going according to my GPS, it was dead on with the GPS with the old tires. Anyway around this or am I going to have to find someone with a Smarty to adjust it, kind of a pain in the ass if so?

[gneal02]

Well a Smarty isn't going to work either, tire size calibration is a VIN locked option.

[icemanjc1]

You could change it with a smarty, then unload it, I know mine stayed. Might work. Unless you want to try a different OS.

[gneal02]

I just went ahead and ordered a Hypertech Speedometor calibrator, hopefully it will work.

[TexasCummins]

The speedometer is controlled by the ABS not the ECM, I too have noticed changing the tire RPM in EFI does nothing. If you have it in with a shop that has a Starscan they can change it from there (as long as the size is in the drop down menu, it's pretty limited and only contains stock-ish sizes).

[mega2006]

So am I reading it correctly that I cant change correct my speedometer error w EFI live? I have been playing around with the "E6500" revs per miles tab. It seem to change the shifting somewhat of the trans but no effect on the speedo. I have been messing w the "E6508" VSS pulses per mile. That seems to have no effect. Any one have a solution for those of us with different size tires?