My SES light came on for the first time ever after taking an off road trip through the desert. I know that you can't check for codes like the CEL. So my question is, how do I know what is causing the light to come on? I did a mild tune-up last February; plugs, wires, air and fuel filter, pcv.

 

The service engine soon light is the same as a check engine light. If you have an Auto Zone near you they will let you use a scanner for free if they have one. Advance Auto will also let you use theirs, Pep Boys won't, they make you pay the $100 diag charge.

 

I have a scanner. Now it appears I have 2 problems. I hooked up my scanner and I don't get a reading. My scanner doesn't even turn on. I tried it on another car and it worked fine. Does GM require a special scanner or is there something wrong with my OBD?

 

Not as far as I know. I used the scanner at my local Advance Auto a few times with no special adapters or anything. To the best of my knowledge OBD2 is universal.

 

So i got my OBD working and pulled a code. P0442, small egr leak. I fount the tube going to the pcv broken in two places and the intake tube disconnected. I replaced the hose and connected the intake. I cleared the code and it hasn't popped up again. Hopefully I didn't get any dirt or moiture to the engine through the intake.