You can actually avoid having to go get it scanned. Just put your key in and turn it to the on position, then off, then on, then off, then on for a third time, and your error codes will come up on the digital odometer. Write them down, then go here
and see what it means. If it needs to be fixed, fix it. If not, either have the autoparts store reset it for you, or disconnect your negative battery cable for about 15 minutes. I've heard that works the same as resetting everything. However, if you don't fix whatever is causing the light to come in, it'll probably just come on again. Hope this helps.