The OBD system in my 2005 town and country is

Your vehicle’s computer system has self-testing capability. When the computer senses that there is a problem with one of the components or sensors it stores the correspondent trouble code(s) in its memory and lights up the "Check Engine" or "Service Engine Soon" light to tell you that there is a problem and you need to diagnosed and repaired it. The list of possible codes number in the hundreds. The code itself doesn't tell exactly what component is defective - it only indicates where to look, or what engine parameter is out of normal range. You or a technician will have to perform further testing to pinpoint cause and the proper repair. Some codes are minor, but if no solved can lead to other problems. I recommend having it diagnosed.

the light is telling u that you have a fault in the electronic controls of your engine, emission or transmission, very seldom do u feel anything in the way the van runs, take the van to any Kragen or Autozone parts store and ask for them to run an OBD 2 trouble code test, it is free, record the codes and post them back on this thread