Somebody just PM'd me today asking if I ever got the problem fixed....
Since it's been a while, has anyone else seen this problem before and figured out what the fix is?
I wish I could say I fixed it. I took the Yukon to a dealer about a year ago; low and behold the dang light went out on the way to the dealer. I figured since the light was on for an extended period of time the PCM would store it as a hard fault. Nope, didn't show up anything at the dealer. I was a little pissed. Not their fault, but still cost me $80 for the "diagnosis" since "nothing" to fix isn't covered under the warranty.
I still have yet to truly find anything specific that would trigger the light to come on/off. Extreme cold or hot weather doesn't matter, driving it hard or easy doesn't do anything either. I've actually been contemplating taking it back to the dealer again - hopefully the light will stay on long enough for them to get the code.
I even took the cold air kit off to rule that out but that didn't change anything either.
I really need to get this fixed before we trade this thing in, as the dealer or whomever will have a heyday with that code if they see it, i.e., "you know, this could cost a thousand dollars to fix so we can't offer you any more than $XXXX.xx dollars for your vehicle."