Came on when I turned the car on. Stayed on for the 30mi drive home from work. Gas cap is tight
Went to Stolhman who pulled the code for me. They told me the code is for the gas cap. I was a little bit suspicious because I have made it a point to tighten the crap out of it. I looked up the actual code P0480 and it turns out to be the code for Fan 1 relay low input.
So, today (2000 miles) the light comes on again with the same symptoms. I pull open the hood and push down on my relays. The one for Fan 1 had some play and I was able to push it down a little bit. Turned engine back on and CEL is now off.
Strange that Stohlman BS'd me with the engine code.