I have a 2006 Chevy diesel with 106,000 miles on it. The check engine light came on a couple days ago. I also noticed that when I start it, the glow plug light does not go off after a few seconds like it usually does. Is there a way to read the code myself or do I have to take ti somewhere? The first two shops I called suggested I call the dealer which I want to avoid and am hoping I might be able to fix it myself.