Illumination of the Check Engine Light can be caused by a loose or worn gas cap.Google+
Car Problem Reports
Chevrolet Trailblazer Check Engine Light Due to Gas Cap Issue
Chevrolet Trailblazer Problem
Average Mileage: 89,419 mi (36,000 mi - 221,000 mi)
I had the tighten fuel cap come on, then the SES light came on. I replaced the fuel cap at auto zone. I unplugged the battery to reset the SES light. It went off. Then driving to work today I got the tighted fuel cap!
Visitor, 2007 Chevrolet Trailblazer, 52,746 mi
I have replaced the gas cap and it still does it at times. I am not convinced that the problem is in the cap, perhaps it is in the sealing surface of the tank neck.
Visitor, 2005 Chevrolet Trailblazer, 73,000 mi
Yeah, I bought my car from the Chevy dealership used. Two weeks after I had bought it, my check engine light came on! So I brought it back to the dealership, and they told me it was the gas cap and it needed to be replaced. It costed me about $100. TWO WEEKS AFTER I BOUGHT IT. Poor customer service, in my opinion.
Visitor, 2006 Chevrolet Trailblazer
My check engine light came on and then I was told that if you have low gas or the cap isnt on tight then the light will come on.. I had low gas so once I filled it up the light went out..
Nice thing to know..
Visitor, 2005 Chevrolet Trailblazer, 50,000 mi
I have put 3 caps on and it stops for a month or two then does it again.
Visitor, 2004 Chevrolet Trailblazer
This happens whenever I change gas stations, so I only fill up at BJ's and the light goes out-lol.
Gas cap failed suddenly. Replaced at Autozone and SES light reset within 400 miles
Visitor, 2005 Chevrolet Trailblazer, 75,000 mi
I have replaced the gas cap I cannot even remember how many times, same problem, check engine light on. My mechanic told me it has always been a problem with the Trailblazer, ignore it he says.....lol. Why hasn't Chevy recalled this and solve everyones problem!
Visitor, 2007 Chevrolet Trailblazer, 111,000 mi
stupuid freaking engine light on!! got the tighten fuel cap message first, then poof! the lovely engine light! replaced gas cap, had light shut off, only to go back on again like 2 days later! gotta get this figured out as I got a rejection for my inspection sticker! ugghhhh!!
About a week ago the gas cap light came on. So I pulled over and tighten the cap, and It went out. So today the check engine light came on and I push the onstar button for them to do a diagnostic test on my truck. After they did the test he said to check the gas cap, and it should go out.It didnt he said if it dont go out in 7 days go to dealer. So tomorrow I will go and get a gas cap and fill my tank up. Wish me luck Trailblazer owners