02 Sedona 3.5L "check engine"

18,750 miles, just coming out of the mountains (approx. 7,000 feet) for a week. Back to the plains, (approx 3500 feet)braked a bit hard for a stop sign I snuck up on a bit fast. The light came on, checked gas cap, (half tank left) eveything performance wise seems fine, finished up the last 350 miles without a hitch. Acceleration, idle, cruise, everything performed flawlessly. You've helped me a great deal with a dealer that doesn't seem to know up from down, so value your opine. Did see something (last spring when you sent the squeaky pulley fix)on a vent tube campaign for high altitude, but when I called him today, said mine didn't qualify as it is driven at about
2000 feet routinely and a short trip shouldn't cause the trouble. The strange thing was it lit when I braked. Ideas???? Thanks Mark