A Loose or worn gas cap may cause Check Engine Light to illuminate.Google+
Car Problem Reports
Buick Rainier Check Engine Light Due to Gas Cap Issue
Buick Rainier Problem
Average Mileage: 74,361 mi (36,000 mi - 120,000 mi)
Visitor, 2005 Buick Rainier, 36,000 mi
My light comes on and I make sure the cap is secure and it is --I wonder why the light keeps coming on
Visitor, 2004 Buick Rainier
Light just pop on checked gas cap don't are any problem with gas cap
Visitor, 2005 Buick Rainier, 120,000 mi
Bought a new gas cap
Visitor, 2004 Buick Rainier, 38,000 mi
removed gas cap and reinstalled. After a tank of gas the light went off. It has occurred twice with same result.
Visitor, 2004 Buick Rainier, 85,000 mi
A Toy Story Sticker solved this one for me. I stuck it right over the indicator light!! THe darn thing comes on EVERY time that I am almost empty. As soon as I fill up, it may go off, it may not. Sometimes I only have to turn the car off, go outside and screw the cap on again. It's not a very smart car.
Visitor, 2004 Buick Rainier, 95,000 mi
Check engine light comes on frequently due to gas cap :(
Visitor, 2004 Buick Rainier, 88,700 mi
Gas cap no longer latches causing the check engine light to illuminate.