Illumination of the Check Engine Light can be caused by a loose or worn gas cap.Google+
Car Problem Reports
Chevrolet Suburban 1500 Check Engine Light Due to Gas Cap Issue
Chevrolet Suburban 1500 Problem
Average Mileage: 100,250 mi (73,000 mi - 137,000 mi)
Visitor, 2005 Chevrolet Suburban 1500
After repeatedly getting a Check Engine light after fueling, I took it to a dealership who informed me that the code that showed up when they hooked it up said that I needed a new gas cap. Well, I paid the big $$ there for the cap and a couple weeks later it came on Again!! This time I took it to my normal oil & tire guy who let me in on the real issue (in my case at least!) I hadn't been tightening the fuel cap enough "clicks"!! I might stop at 2-3 & he said turn til you hear at least 10! Otherwise the vehicle senses that as a "leak" in the fuel system, be it fuel or air/compression. This happens quite often in many other makes/models too! Hope this helps someone!
been there done that
Visitor, 2006 Chevrolet Suburban 1500
Check engine light stayed on and once the cap was replaced, it stopped.