A Loose or worn gas cap may cause Check Engine Light to illuminate.Google+
Car Problem Reports
Hummer H3 Check Engine Light Due to Gas Cap Issue
Hummer H3 Problem
Average Mileage: 80,007 mi (34,500 mi - 120,000 mi)
Visitor, 2006 Hummer H3, 62,000 mi
Engine Light will not go off. It will read fuel cap every now & then. We have tighten the fuel cap and the light is still on. Not sure what to do. It is out of warrenty and I have no money
Visitor, 2006 Hummer H3
my check engine light came on with fuel cap loose light
Engine light on, fuel cap light comes on after five miles of driving. Plug-in testing reveals unidentified vacuum leak. New cap for 30 bucks does not restore the loss of faith in a part that should last longer than five years.
Visitor, 2007 Hummer H3, 58,000 mi
Check engine light is always on and my dash blinks fuel cap
Visitor, 2007 Hummer H3, 70,000 mi
Same issue, bought a replacement gas cap didn't fix it. I would notice the gas cap would get loose after driving a couple times. Replaced with a new factory cap from chevrolet.
Visitor, 2008 Hummer H3, 58,200 mi
Driver information says gas cap loose and check engine light is on.
Autozone checker says evaporative system or gas cap.
Visitor, 2006 Hummer H3, 34,500 mi
The gas cap strap got wrapped under the cap after refueling causing the cap not to seal properly. This caused the check engine light to come on until the gas cap was sealed properly.
Visitor, 2006 Hummer H3, 113,000 mi
Check engine light comes on alot. Tighten gas cap and goes off in two days. Not fixed
Visitor, 2006 Hummer H3, 94,333 mi
engine light keeps comming on ,change gas cap worked for 3 days back on again
Visitor, 2007 Hummer H3, 75,000 mi
Same issue....check engine light comes on over gas cap