thanks guys. I'm calling now to make an appointment.

 

You might also want to check one of these out. I picked one up and its really great. Scan and clear engine error codes, even get live diagnostics to make sure your MAF is working properly..etc..
If you are comfortable with a soldering iron, they even have plans to build your own or get a protocol specific one for much cheaper. You can easily put one together for less than what the dealer charges to do a scan. Anything that pays off after the first use is worth it to me.
http://www.scantool.net/products/index.php?cPath=8_6

 

Well, the light went off last night and I called onstar, they ran a diagnostic check and found nothing wrong. I think it was the gas cap. Still have to bring it in cause I have only one headlight so I'll have em check for codes then.

Ghost, thats pretty cool, most scan tools I have looked at were way more money than those. I may have to pick one of them up. Thanks for posting.