Something you may consider is to have a place like AutoZone read the code for you at no cost and have them reset it. They may also be able to tell you what is causing the problem like maybe a loose gas cap or something easy that has been over looked before.

They can also reset the CIL and your mpg shoudl go back up BUT of course, the service center wont have a code to be read is someone else clears it before they see it.

You do have some choices, make the best one that fits your schedule.