Here's the scoop. I tuned an 06 Tahoe Z71 with Stabilitrak a couple of months ago by mail. Met up with the guy yesterday and adjusted the tune for his new, larger tires. Immediately upon re-flash, DIC shows that the stability control system has been de-activated. Pull the DTCs and see a C0558, "Calibration Data Not Programmed", Status: PHC, Module: ($29) "Electronic Brake Control Module (EBCM)"

I'm assuming that the cause of this is much the same as when you drastically change tire size and the ABS computer begins to freak out.

Has anyone run into this issue before? And if so, did you manage to get it fixed? Tire size increased by about 7.5%.

Thanks,
Justin