It won't erase it. The only thing in the pcmis the axle ratio. I would try a returnto stock, thencallibrate the speedo only,and plug it up to another 5.2/5.9 and see if it is vin locked. That's nice that the Hyp. has that feature. I was pissed that the Superchips wouldn't leave the callibration in there. I wasn't going to keep it around and not sell it just for that, and I am determined not to let a stealership touch my pcm ever again.I have just learned to live with my speedo being off bylooking at rpm's.

If you listen carefully, when the speedo is being callibrated you will hear the module behind the dash make a clicking noise.

 

Thanks, I'll try that.