Quote Originally Posted by koryenger View Post
I am having the same problem. 2011 Suburban 6l80 and everything I try is not making a change. I went +/- 10...20...30...40% on the H0105, messed with gear ratios. The vehicle has a 6.0 gear in it and 40 inch tires. Basically what I am seeing on a scanner is almost double of how fast the vehicle is going. Anyone have any suggestion on this?
I have had no luck with two 2011 Silverado's correcting the VSS. Any changes I make to the speedo parameters or gear ratio's have no effect; similar, to the problem I had a few years ago with the 09's.

I ended up using HPT and Hypertech to calibrate the VSS on these vehicles.

Any help is appreciated.