Illumination of the Check Engine Light can be caused by a loose or worn gas cap.
Yukon XL Denali
Average mileage: 92,555 (35,000–189,000)
24 people reported this problem
Viewing 1 - 7 of 7 comments
Check engine light on for one day; checked gas cap and was loose so tightened it. Check engine light still on one week later
Was on the freeway. Lost almost all power/acceleration. Pulled off freeway and called dealer. Check engine light was on. Car lurched along when trying to go. Dealer said maybe gas cap was loose. Opened gas cap, turned tightly to hear three audible clicks, then started and stopped the car 10-12 times (per Dealer instructions) and the problem went away. Same thing happened to my sister's 2000 Denali. Same solution worked.
Indicator light, diagnosis engine reports gas cap issue
Check engine light due to gas cap issue.
Check engine light goes on and off
This has happened twice that the check engine light came on with the message of tighten gas cap
Check engine comes on. A bottle STP gas treatment or dry gas fixes it.