Illumination of the Check Engine Light can be caused by a loose or worn gas cap.Google+
Car Problem Reports
Pontiac G6 Check Engine Light Due to Gas Cap Issue
Pontiac G6 Problem
Average Mileage: 92,735 mi (25,000 mi - 190,000 mi)
Visitor, 2006 Pontiac G6, 75,000 mi
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...
Visitor, 2009 Pontiac G6
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
Visitor, 2005 Pontiac G6, 80,000 mi
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.
"Check Engine Light" stays illuminated when car is on. Replacing gas cap did not fix problem.
Visitor, 2006 Pontiac G6, 90,000 mi
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.
Visitor, 2007 Pontiac G6, 43,120 mi
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?
Visitor, 2006 Pontiac G6, 71,000 mi
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.
Visitor, 2006 Pontiac G6, 29,100 mi
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?
Visitor, 2005 Pontiac G6
Replaced gas cap twice, lines checked for vacumm loss, sensor replaced, still having the issue
Visitor, 2006 Pontiac G6, 60,000 mi
Check engine light will come on due to issue with gas cap