Check Engine Light Due to Gas Cap Issue on GMC Yukon Denali

Problem Description and Possible Solution

A Loose or worn gas cap may cause Check Engine Light to illuminate.

Problem Data
RepairPal Verified
Average mileage: 100,547 (30,000–190,000)
12 model years affected: 1999, 2000, 2001, 2002, more2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
55 people reported this problem
Viewing 1 - 20 of 22 comments
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
Gas cap sensor triggers check engine light. Despite replacing gas cap at the dealership the light goes back on.
"tighten fuel cap" persistent problem, replaced cap, replaced tank vent solenoid (that fixed the slow fuel fill problem). Cleared faults for about a month then get a periodic "tighten fuel cap" and check engine.
Check gas cap light came on, tighten gas cap. A day later the light came on again. We replaced the cap. A week lated it happen again.
replaced the cap. Went off for on day and came on again. Went to auto zone they found code was for purge solenoid.
Replaced solenoid.
Engine light due to gas cap
wire that connects to rear window defogger has broken off
My check engine light came on and i took it in to get it diagnosed. it was a gas cap leak. they replaced it with a factory gas cap. i had an aftermarket locking cap before.
check engine light
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...
I have same this problem, then I change gas cap thenthe problem fix
replaced, gas cap and removed negative battery term for2 min. light went out.
Gas Cap Seal
Worn gas cap causes check engin light to come on. Only the $25 GM cap works to fix the problem.
Check engine
Engine light on.
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.
Not fixed after buying two gas cap from GMC dealer.
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.
Got a diagnosis with a code using the code machine...the code could have been a couple things related to gas, but it was determined that it was just that the gas cap was too loose ....just replace the cap.