I'm running OS 12579357.
Yeah, if anyone had any tips as to what values might affect the speedo readout at all, I could work on figuring out the equation, but so far I haven't been able to generate any change whatsoever with H0101, H0104, H0105, or B0205. I've given up on the speedo calc tool and was just entering in values manually. As I mentioned before H0101 does inversely affect the VSS reading though.
I checked out the GM website... here's what I get:
Calibration History for: Speedometer
Part Number CVN Bulletin # Description
12580498 00008583 - Part number change only, same as prior calibration
12574176 00007291 - Speedometer calibration
Any idea what this means?