From miles 300 to 600 or so, my check engine light was one. Had it at two different mechanics, Morgantown WV and Lewisberg, and they couldn't figure out why. After one trip to the PA dealer, maybe a couple of hours driving after getting back, it went off and never came back on.
There's a different mechanic there now, but I don't remember him ever mentioning messing with the ECU, other than to reset the codes. The gist I got for all the mechanics was keep an eye on it and see if there is any other indication of an issue.
It's not come on in the thousands of miles since, so maybe the bulb burnt out.
