Check Engine Light Due to Gas Cap Issue on Pontiac G6

Problem Description and Possible Solution

Illumination of the Check Engine Light can be caused by a loose or worn gas cap.

Problem Data
RepairPal Verified
Average mileage: 96,051 (15,789–190,000)
6 model years affected: 2005, 2006, 2007, 2008, more2009, 2010
102 people reported this problem
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
Viewing 1 - 20 of 52 comments
UPDATE WE FIXED THE PROBLEM ON OUR CAR! COST FOR PART $35 AND TOOK MY HUSBAND 5 MINUTES TO REPLACE. PART FROM NAPA VALVE/SOUPAPE #2-282570 #V13030 ENGINE MANAGEMENT PRODUCTS . HOPE THIS HELPS EVERYONE ELSE THAT IS HAVING THE SAME ISSUE WE DID.
For months now the dash will beep and flash "Check Gas Cap", we've changed the dang thing twice now and this still keeps coming back. Only happens after we clear the code and then gas is put in, and it does not just go on and off, it stays on until the code is cleared again, then stays away until gas is put in. Annoying to say the least...
"Check Engine Light" stays illuminated when car is on. Replacing gas cap did not fix problem.
Not fixed yet...... 2 gas caps ( aftermarket and 1 factory cap. I get the chweck fuel cap and then the check engine light. Now what?
I bought my 2005 Pontiac G6 used. One day I put a CD in the player and it didnt work. My CD is still stuck in it. Then right after that happened. (minutes after)My "check gas cap" light came on. I pulled over checked it. It was on. The gas cap seems like it is worn out. I dont know. Its hard to get it off and on when getting gas. Gonna get a new cap and see if that works. I also noticed that when I start it I have to rev the gas so it starts.
I've put grease around the ring of the cap, replaced the cap (twice) and light still comes on .... now I see why this was the last year for G6's to be made ... sheesh
Tried tightening cap deal and same results. Replaced cap and same results. Had AutoZone read codes and cleared. Code was gas cap. After clearing lasted 2 days! Very annoying, don't know if I have another problem (with gas cap crap, check engine light; or a real problem). Now I do a search and find many other people having same problem. This the only real problem I have had with the car and love scoot power of the V6 when I need it,along with 30+ MPG! Looks to me like a design flaw whether intentional or not! Beginning to wonder about and I am going to check for a recall or service bulletin.
gas cap comes loose and have to open and close and then it will engine check light goes off. Then the next day or two it does the same thing. Have replaced it once and will try and replace it again. Crazy. How or why does it always work it self loose?
Check engine light will come on due to issue with gas cap
.Engine light keeps coming on after putting gas. Took it to dealer no problem found.
Car has lot of highway mile but runs excellent .
Replaced gas cap twice, lines checked for vacumm loss, sensor replaced, still having the issue
Replaced Gas Cap, Service Tech has already smoke checked. They can't find anything yet the light is still on. Sometimes can't start in the morning.
Cap warning light and now engine symbol is on. Gas guage goes all the way to empty when on 1/4thh of a tank. Today the car stalled and cut off like I ran out of gas, I had to pull over and then I restarted the car and Drove it but gas guage went all the way down to empty!
engine light comes on intermittently, usually within a few miles after getting gas
First the "check gas cap" comes on, then check engine light comes on. I have replaced the cap twice. This problem is so very annoying. The dealership wants $90 just to hook it up to their computer to detect the real problem; however the $90 does NOT go toward the repairs, it is the cost to diagnose the problem. The dealership mechanic says it has to do with a leak within my emissions system. I really love my G6, but I have had to pay for replacements of parts even when it was still under warranty. Now I am finally getting the possible reason that GM cut the Pontiac division and the "G"series were discontinued.

Both my keyless entries (remotes) stopped working at same time some for (4) years ago. The dealership said this is very normal, the remote generally goes out after about 3 years.
message system states that gas cap needs to be checked
Problem came right after new battery was put in. It has never happened before. I taken it off and placed it back on making sure it clicks. Why now
Check engine light due to gas cap displayed and gas metor started decreasing showing I was burning gas at a rapid pace. I pulled over, and after pulling over checked the cap, and the cap was fine. Got back into my car, and the check engine light was gone. As I started to drive, my gas gauge started going back-up to where it was prior to the check engine light coming on.
Gas cap not the problem if engine light still comes on. The problem is usually with the Solenoid Vent Valve, especially if having trouble getting it to start up when cold. Finding a mechanic to take the time to lower the gas tank by 1-2 inches to replace the valve has been difficult. Also, flex pipe of left catalytic converter needs replacing.
Has not been fix yet, but the engine light goes away after fiddling with gas cap.