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: 98,954 mi (60,000 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!
Visitor, 2005 Chevrolet Suburban 1500, 120,586 mi
Check engine light is still on. Just replaced gas cap.
Visitor, 2003 Chevrolet Suburban 1500, 60,000 mi
Check engine light came on and would not go off. Repairmen checked vehicle w/instrument and item was corrected
Visitor, 2007 Chevrolet Suburban 1500, 104,000 mi
Check Engine Light due to emissions issue that sounds like this one. Tech ran OBD2 scanner on it and found the code related to a fuel system emissions problem. Gas Cap is suspected.
been there done that
Visitor, 2006 Chevrolet Suburban 1500
Check engine light stayed on and once the cap was replaced, it stopped.