Check engine light and trac control

Today my check engine light came on. Im gunna get that checked at autozone sometime in the next few days. But i noticed that when my check engine light is on, i cannot turn my trac control on/off. Thats when the car is running, however if i turn the key to the on position i can turn the trac control on/off. So im wondering if the two are related. With the check engine light, im not sure if it is the o2 sensors, because they were supposedly replaced when i bought the car about 3 months ago. So im just gunna have autozone check and then go from there. But if anyone could give me some info about the trac control, i'd really appreciate it.

I finally got a chance to look under the hood and mess around with some things today, and i noticed that my fan is constantly on. I had my car running for about 10 min, and the fan was on all the time it was running, it came on as soon as the car started. Any ideas?..I dont know much about the pontiac engine..so any help would be greatly appreciated.

First thing you need to do is have the codes pulled to determine where the problem is.
When the SES light comes on and the PCM stores a code, the PCM cuts off Traction control until the problem is fixed and the PCM is reset.

I disconnected the (+) cable and reset everything. The light went off, and hasnt come back on, and i drove pretty much all day today. If it comes back on then ill get them read. Thanks for your information on the trac control though, i figured that may be it, but i wasnt sure.

I recently got the codes run, they said it was the emmisons control something or other. The guy said it was from a loose gas cap, or me trying to fill my car to the max (gas). Whereas i always make sure my gas cap clicks, and i usually dont fill the car way up, usually til the pump shuts off by itself. So i dont get how it could have happened. Also i dont see how this relates to my engine fan bien gon anytime the engine is on. Maybe the fan is getting a reading that the engine is hot? Any help would be greatly appreciated. Thanks