CMF Veteran Member
Join Date: Jun 2008
Location: Southern Delaware
Re: Gas cap light... serviced 6 times
I had almost essentially the EXACT same problem with my ex '08 Pontiac G6 GT coupe, starting the very first morning I had it, the day after picking it up. I drove a mile after it sat overnight and ding-ding-ding "Check Gas Cap" came up on the DIC. I thought it was just a randomly loose gas cap that time, but it eventually turned into 3 months of it happening every week, usually a full day or two after I filled up over the weekend and had then driven to work and back once, and in a few occasions I also had the smell of gas in the car--that was rare, however.
Mine, in total, occurred 17 times in 3 months and it was into the dealer either 3 or 4 times for it, along with a couple of other things that were ongoing. They tested it, it was okay, tested again, okay...kept happening and eventually I filed a BBB Autoline claim, started that process with GM, etc. requesting either a fix or an equivalent replacement, and eventually the "final repair attempt" was scheduled. Dropped the tank, replaced the sending unit & fuel pump, did more checking, and gave it back to me 3 days later. Ran just as it had before, and within a day or two the "Check Gas Cap" alert was back, along with a newly fluctuating gas gauge up and down randomly, and the Check Engine light randomly a few days later. From the start I videotaped & uploaded everything, sending it to my GM rep along with the other dealer, etc. docs, and always did an Onstar diagnostics call when it would come on, and a week after the repair when I confirmed it not only didn't work but things were worse, I was offered the trade buyback just as I had requested. In came then my '09 Malibu 2LT, now also gone for other reasons.
So, yeah, I've had the issue and with the same platform/family of cars, but rather the 3.5L and a G6. At the time my dealer actually told me they had one case a couple of years earlier with a lady's G6 and the same Check Engine light, and after a few unsuccessful attempts, GM said to swap out the sending unit and such--which fixed it. Didn't for mine, and only resulted in more problems. Still have no idea what might have been the problem as the car was repurchased, sent through the GM process and then resold at a dealer...but I continue to wonder. It was truly bizarre.