If it's a nag light, doesn't that have to be corrected prior to extracting codes?I suppose that this post is not the forum for me to discuss 'empowering' yourself. If your check engine light has been on for 2 years, and your mechanic has not attended to this....well, you can try yourself. It is incredibly easy to do, and I assume that, the South notwithstanding, they have metal paperclips there!! If you read the Check Engine light link in the earlier post, you will be able to follow the instructions easily. Autozone or O'Reilly's will NOT do this for you!!
Again, there are a number of things under the dash that can click - it may very well be your computer - or it could be the wiring/power running to it as well. Of course, it is certainly your choice to choose to spend $100-400 on a replacement computer, along with the possibility that this does not solve the problem.
Your computer is located just behind your left front speaker. If you stick your head up under the dash in that area, you will see the bottom of it, which will have a sticker on it that says 33920-XXXXX. It's the X's that will give you the model number - chances are your model number is 33920-70EA0