I recently purchased a 2013 GMC 3500 diesel truck and on the dic it will give me average MPG and the owners manual states that instant mpg is available if so equipped. My question is is it a software...
My '09 2500 doesn't have instant, just average. I test drove a '13 LTZ 3500 D/A and I am almost positive that I remember it had instant. I figured that was an upgrade from the older models.