If you go to any AutoZone, Advance Auto Parts, Bennett Auto Supply, O'Reilly's Auto Supply, Etc... (Whatever is near you) They will use an OBDII Code Reader tool and pull the code and give you the Code # and usually print-out of what is GENERALLY the reason for the code being thrown.
More than likely, it is something stupid. I bought a brand new car a few years ago and after only 400 miles my car was running terrible and threw a CEL light. After the dealer checked it out it turned out to be water in the gas tank. I guess the gas station I went to for my 1st fill up (after dealers free tank when I bought it) had bad gas/water in the fuel mix. They drained the tank and cleared the code and all was good.
So.... don't freak out, however, I wouldn't wait until Monday. Just get the code so we can get a better idea for you. You gotta remember that just because a vehicle is brand spanking new does not mean that they are immune to problems. They are still assembled by humans and the parts that they are made of are not immune to manufacturing defects. I am sure this is common knowledge but some people act like just because something is new that there couldn't POSSIBLY be any issues... LOL
Even 400k brand spanking new vehicles have issues. This is the entire reason they are required to give you a manufacture warranty.
I suppose that this is just karma. The vehicle I traded in had the check engine light on. It came on a few weeks before my truck came in and my mechanic said it wouldn't be worth the $ getting it fixed.