My '07 had the light come on after I had changed the gas cap to a locking gas cap; (don't ask...I was on the net late one night and thought a locking cap would be a good idea. Didn't recall the car has a locking gas door until after the cap had arrived). I had read somewhere that not tightening the cap could cause the check engine light to come on. I put the old cap on, tightened it 'til it clicks a few times. About two days later the lights went off and they've stayed off for several thousand miles, now. The check engine light problem could be just that simple. Try it before spending any extra dough on sensors or catalytic converters.