Grinding/stuck noise and check engine light?

I'm hoping someone can help me figure out what's wrong. I have a 2000 Cavalier w/ about 76,000 miles. On my way to work this morning, my check engine light came on and I noticed when I either braked, turned or accelerated I heard a grinding noise like something was sticking. Does anyone have any ideas what the noise is, and is that what is causing my check engine light to come on? Thanks!

you probably have a hub bearing going bad, and the check engine light came on due to the wheel speed sensor indicating different wheel speeds, which will trigger a traction control code

Any ideas how much this may cost to get fixed?

The part should cost less than $100, the labor shouldn't exceed $100 or so either. IF you can do a brake job, you can replace a hub bearing. Get a repair manual and save yourself the labor cost. You'll need a 30mm axle socket (you can rent this for free at Auto Zone) and a t-55 torx to remove the hub from the spindle.

Okay, now I feel like a real dummy. I had a friend look at the car last night, and lo and behold, the check engine light came on because my gas cap wasn't on properly. The grinding/stuck noise (which I never heard before) was my roters getting ground to a pulp.

Thank goodness it wasn't a bearing or something!

~Jessica