Truck is an 06 duramax


I'm running v7.5 and can't get the speedo to do a fine tuning calibration. It shows the percent correction I need to do to H0101 but the pulses numbers don't show up and I can't manually change H0101. What am I missing here? I can change tire settings so I could guess at those until I get it correct but if there's an easier way I'd rather do it that way.