Hey guy's, my check engine light came on the other day then went off. I took it to a local GM shop to have it checked out. The service writer told me that it was something to do with the glow pug system. I did not get the code from him but he did say that it could be something as simple as a loose wire to one of the glowplugs. He reset the computer and a day later the light came on again.
I notice now that sometimes it will be on and the other times off, mostly when I first start my rig.
I have not noticed anything out of the ordinary and it still starts just as it did when I first got it.
Is there a poor mans way to check for codes without investing in a special tool?
Thanks in advance, Marco.
2002 LB7

You may try autozone to see if they can read them.

or, if you put where you are from in you signature...you might could hook up with someone with a Predator or some other diagnostic code reader.