Check Engine Light

Well the check engine light came on when I was on my way to work this morning, this really sucks, now I gotta go to the dealer and get it checked out. I will let you all know what it is when I find out. It came on when i was just driving normal down the road, hope its nothing major.

Eric, how is it running?  Smooth, no misses, smooth idle?  Have you switched gas stations or changed anything just before the light?  Can be something really simple, and often time is.  Good luck brud!

My CEL (check engine light) came on a week ago, I thought it was due to gas cap not sealed right or something.  ON-STAR even sent me an email saying my CEL was on and to call ON-STAR and they can do a diag check right through them.  He listed a few thing to check out.
Comes to find out I had low air all 4 tires. Once I filled them up, light went out and has not been on since Sunday.
 
 

I posted this under another CEL and it was helpful, let's try it again.  If you go to your local major autoparts dealer, most have a scanner they will hook up and read the code for free.
 
 

Tires are all good
 
I did fill up at a different gas station, ADMIRAL - some cheap gas station in town, I usually never go there because its a dump. I hope this inst what happened.
The hummer is running smooth, dont think its miss firing or anything. I get it back from the dealer tonight, I will let you all know what happened.

Ebrown i had the same problem next time read your hummer h2 book to find out . Your light came on because of the gas you put on your hummer i did the same thing with the same gas and it came on . I when to a  parts house and i put in the gas tank a can of gas water repellen . RA     

Does it seem a little sluggish on take off?  May be loss of compression in a cylinder.  That's what happened to me when I bought mine in 06, bitched about it and they gave me an extended waranty to 100,000 miles on all engine parts.  One thing I learned...NEVER buy a first model year.  If you complain enough they will extend your warranty, don't give up.  May also be a bad spark plug, had that happen as well.  As bad as I want the HX in 2010, I'll wait this time.

Sorry, thought you were talking h3.

my CEL came on at 60k miles. Turns out mine was the evap sensor and cylanoid. So i bring my baby into the dealership and everything is covered under an extended warrenty i just purchased about 2 weeks prior. So it cost me nothing. They also said my vent were clogged with mud and dirt.. go figure
 
GL.