A Loose or worn gas cap may cause Check Engine Light to illuminate.Google+
Car Problem Reports
Buick LaCrosse Check Engine Light Due to Gas Cap Issue
Buick LaCrosse Problem
Average Mileage: 50,766 mi (10,200 mi - 80,000 mi)
Check engine light stayed on. Remote diagnostic (Onstar)indicated that problem was with the gas cap. Took car to dealer, told them and they replaced the cap. Problem resolved.
Visitor, 2008 Buick LaCrosse, 80,000 mi
Check gas cap light keeps coming on intermittently and now check engine light on. Replaced gas cap
and okay for awhile. Both engine light and check gas cap light went off. Now, back on again.
First check gas cap (which I did) and now engine light.
Visitor, 2006 Buick LaCrosse, 52,000 mi
I have selected "me too" to 3 other common problems with the Lacrosse. I contacted buick for assistance on repairs and they said Garber Buick in Saginaw Michigan would only agree to $50 assistance on a $443 repair bill. How sad! But they had no problem taking bail out assistance from my tax paying money!!!!!!!!!!!!
We had this issue too. Mechanic found the problem.
Visitor, 2005 Buick LaCrosse, 37,000 mi
Check engine light
Leak in pressurized system
Gas inlet defective
Replaced $77 at dealer
Visitor, 2010 Buick LaCrosse, 73,000 mi
Check engine light is on and the dash reads "Tighten Gas Cap" . I've tightened the gas cap several times I'm taking the car to the dealer tomorrow.
Visitor, 2005 Buick LaCrosse, 60,000 mi
Replaced gas cap. Problem returned again, 3000 miles later
Visitor, 2008 Buick LaCrosse, 22,098 mi
gas cap light cap looks ok then engine check light guess I should of bought a donkey
Visitor, 2006 Buick LaCrosse
LaCross has done this since day one I have had it back in a dozon times and was told that sensors are to senitive. this is from dealer!
Visitor, 2007 Buick LaCrosse, 55,000 mi
Check engine light and loose gas cap information came on at same time - but cap was tight. Dealer had better price on cap than parts stores. Issue solved.