If you didn't lose any power AND the light came on when you or after you accelerated in 5th ... it may just be a sensor and clear itself after a few days.
Can't remember the exact code but AR had the same thing happen and CEL went out in a couple of days.
Still, have it read to see what the code was ... if its not something serious, let sit a couple of days and see if it will clear itself.
Here is a list of the codes:
Same Problem Over and Over
