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: 63,394 mi (10,200 mi - 110,000 mi)
Visitor, 2005 Buick LaCrosse, 37,000 mi
Check engine light
Leak in pressurized system
Gas inlet defective
Replaced $77 at dealer
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, 22,098 mi
gas cap light cap looks ok then engine check light guess I should of bought a donkey
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, 2008 Buick LaCrosse, 89,000 mi
Always low feul gas cap or chek gas cap
MY CHECK ENGINE LIGHT IS ON AND MY ONSTAR DIAGNOSTIC IS SAYING THAT IT HAS SOMETHING TO DO WITH THE EMISSION SYSTEM.
check gas cap would come on if you did not clear it then check engine light comes on