JAY4SPEED
May 5th, 2009, 06:05 AM
I have a customer that installed 26 inch wheels on his Avalanche. His speedo is off 3 mph. I have a correction factor of .9375. I tried to apply the correction factor to H0135, H0136 to no avail. I've also changed the TCM H0136 to the same as the ECM's value (incedentally the value for TCM H0136was not even close to the ECM). I did measure the new wheel rollout and applied that to H0139 / H0140. Flashed both and I'm still 3 mph off. I've tried all different combinations of applying the correction factor to H0136 and leaving all others stock, or applying the correction factor to H0135 and leaving the others stock etc. Nothing seems to work. Attached are both the stock ECM and TCM files. Thanks for any help.
Jay
Jay