check engline light just came on 2004 freestar?

Can you find out what the trouble code is that the check engine light is giving out? You say that there are no syptoms present with the light? Did you just fill up the gas? sometimes if the gas cap is put on incorrectly, the light will come on because the system is losing pressure. Try fixing the gascap and see if the light goes off. If not try and figure out if anything seems out of the ordinary. It is hard to figure out what is wrong if you cannot get a code or find any symptoms