A Loose or worn gas cap may cause Check Engine Light to illuminate.
Car Problem Reports
GMC Yukon Denali Check Engine Light Due to Gas Cap Issue
GMC Yukon Denali Problem
Average Mileage: 85,427 mi (50,000 mi - 145,000 mi)
check engine light came on and message appeared that the gas cap needed to be tightened. had diagnosised to determind gas cap was no longer sealing properly- replaced gas cap, but check engine light still on
Visitor, 2004 GMC Yukon Denali, 70,000 mi
Engine light due to gas cap
Visitor, 2003 GMC Yukon Denali, 145,000 mi
MIL light comes on right after I fill gas tank and drive at speeds over 70 MPH. New O2 sensors, New air filter, new spark plugs, new plug wires, and I still get a P300 trouble code. (Random multiple mis fires). No help from Dealership other than an offer to TRADE IN TO buy "THE NEWEST CROWN JEWEL". Well, BS to that...
Visitor, 2006 GMC Yukon Denali, 69,851 mi
I got a message on dash telling me to tighten the gas cap. I thought this was strange sine I hadn't gotten gas for about a week. Anyway, I tightened it for chuckles. Next day, I got the same message and did the same thing. Then I got the indicator light for the gas. I called on-star to do a diagnostic system check. They said tighten the gas cap and if the problem persists, go to the dealership for service.
1)"Tighten loose gas cap" warning message came up twice in the message display.
2)"Engine light" illuminated on the dash cluster.
3) Gas cap WAS loose, re-seated & tightened cap - haven't replaced, yet. Will recheck this PM.
Visitor, 2008 GMC Yukon Denali, 89,000 mi
I have an 08 denali with the WORST gas cap. It is very hard to get it to seat flush. I constantly get the check engine light because it doesn't create a seal when it's on.
Visitor, 2005 GMC Yukon Denali, 51,000 mi
Check engine came on. Onstar said it was not a serious problem. I replaced my gas cap with a new one and after several days, the light went away. Onstar said no proplems.
Visitor, 2006 GMC Yukon Denali, 50,000 mi
Worn gas cap causes check engin light to come on. Only the $25 GM cap works to fix the problem.