Thanks for the diagnostic chart! I had cleared the codes after reading them and they have not come up again, been almost 1K miles and all is good. I'm wondering if it was a fluke one-time event, or a preview of upcoming issues. This truck has been very solid and reliable so far, my fingers are crossed that things will remain so. 137,000+ happy miles, I keep telling myself I don't need to upgrade to a new truck. Over and over...