I recently purchased new tires for my 03 GMC 2500HD Duramax Diesel. The stock size is 245/75 and I moved up to a 285/75. This changed the ratio on my speedometer, Driver info Center, and Odometer. The DIC cannot correctly calculate MPG, range, or average fuel economy anymore, also the speedometer is about 8 mph off. Is there a chip I can change or reprogram the ECM to accomidate the new tire size?
Sincerely
Shawn Timothy