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: 68,328 mi (10,200 mi - 167,000 mi)
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, 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, 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
I had the same problem with the check engine light always coming on. I would remove and replace the cap quite often and the light would eventually go off. Finally that stopped working so I went ahead and bought a new cap. Replaced the cap, filled the tank with gas, added some of that adatech additive for good measure, and the light went out the next day. It was worth a try because the Buick dealer would charge $130 for a diagnostic on the check engine light. Gas cap was $16 online. Another blog site mentioned putting vasoline around the seal area of the cap. Might be worth a try before getting a new cap. If my new cap starts acting up, I'm going to try the vasoline thing. Makes sense....as it does appear to be related to the seal.
MY CHECK ENGINE LIGHT IS ON AND MY ONSTAR DIAGNOSTIC IS SAYING THAT IT HAS SOMETHING TO DO WITH THE EMISSION SYSTEM.