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"Check Gas Cap" Alert

Just recently I've been getting a Check Gas Cap alert on my computer display. This happens every time the car is started and won't go away. The gas cap is screwed in securely and the lid is closed with no change. What's going on?!

-Kevin
 

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Do you think that this is something that simply needs to be acknowledged? The same way the “change oil” indicator shows up.
 

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Oddly, my 3 week old one did this twice too. First time the morning after I brought it home and was off to work "Ding, ding, ding...Check Gas Cap". Pulled over and checked it but it was already as tight as it should be.

Then a week later, at exactly the same distance down the road from home, same thing. This one I just ignored and I haven't seen the alert since.

The gas cap messages and/or check engine lights related to them can often take quite a few restarts to clear, at least with some other vehicles, so I don't know if someone just drove the car early on with it loose and set the code or what, but it seems fine now. Weird, regardless.
 

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When you fill up and put your gas cap back on you need to be sure it clicks like 4 times.

If you do the the code it'll take about a week or so for it to cycle thru the ECM and be clear. Usually there is a way to clear it in the car (starting the car with the ebrake on, going 100% on the brake a couple times, turning the wheel, turning off car, turning on car, turning off car, that kind of shit). If it is really annoying, buy a scan gauge to clear it yourself...... then return to where you bought it. :)
 

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Well after 3 times of it coming on, and the car--I swore--feeling a hair different when it did so (like stumbling, barely), they cleared the code. All was well for about 2 weeks, then Tuesday I felt the car seeming to studder as I pulled out of our street slightly and that "not right" feeling again only for the light to come on a 4th time.

They still don't know what, if anything, is going on because nothing ever happens when they have it. The cap is clicked at least 6-7 times (well aware of the loose cap issue, on any car) and yet this continues to happen, so I think there's another leak. Nothing found all day, hence I'm crazy again, so the service manager took the car for the night home to drive and see if anything presents itself. This gas thing alone is driving me nuts!
 

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Great! I'm now up to SIX times of the alert coming on regardless of the cap (which is always tightened) AND the car runs oddly at the same time. After twice at the dealer for this and the second time them doing NOTHING because the alert wasn't on for them (it's only on for a minute at most as is...how the heck could I bet on it just turning on for them? Insane.).

Oh well. With this and other issues, I've started video taping while driving and caught it this morning followed by a call to Onstar just to have further record. Dealer is incapable apparently of doing more than a visual so it's one of the things I started a case with Pontiac over.

We'll see. Anyone else have it come on, oh, 6+ times and have a car not running on full fuel at the same time?
 

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I am having a similar problem as well. At times, the car stalls while at a light, and I get the message to check the gas cap.

Any thoughts?
 

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have you had any luck with fixing your gas cap problem iam getting the same message now and im wondering what the best fix is ........
 

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The EVAP monitoring system, which triggers the "Check Gas Cap" light, can detect a leak around 2mm..so, if the gasket on the gas cap has a small tear, it can trigger the light. It's cheap and easy to try a different gas cap if you're persistently getting this issue.

If that doesn't do the trick...well, it could possibly be an EVAP leak somewhere else. I remember reading on the Chevy Malibu forum about someone who was having the same issue... might be worth it to check it out.
 

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Could be a couple of things. That gas cap warning is going to set a soft code for your EVAP system. So you could have a leak in your EVAP canister, one of the lines or the cap itself. This code is trigger when the sensor detects a change in vacuum.

My car did this and I just cleaned the gas cap seal with a bit of alcohol and lubed it up with some petrolatum. Fixed my problem, you may want to try that and then clear your code using a scan tool, dash hawk or disconnecting the battery. If you disconnect your battery be sure to turn the radio off first or you could fry it.
 

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Check Gas cap

I've got an 06 G6 GT with almost 120k miles on it. "Check Gas Cap" started a few months ago. I finally bought a new gas cap at Auto Zone and I thought I fixed the problem. My husband started driving it and said he never saw the warning again. But of course, the first time I drive it after the new gas cap, it dings and shows "Check Gas Cap" again... and... drum roll... Then I got the dreaded check engine light! Checked the code on that at home and it was PO455.
I took it in. It's been at AAMCO since Monday. They said it was throwing 4 codes. They are charging me $400 to run diagnostics on all four codes. It's now Friday and I still don't know what is wrong with it. I think my AAMCO is under new management and they are probably screwing me. The only reason I took it there is because I had a similar issue with a different automobile about two months ago, and they had awesome service and went out of their way to help me and to not screw me. So, I am probably very, very screwed right now.
I have done every scheduled maintenance on this car (and then some). Besides putting four or five sets of rotors and 6-8 sets of brakes on this thing, and constantly having to get it aligned and balanced, I really haven't had any "system" trouble with it. It got new spark plugs and lots of new goodies, and it recently passed its smog check.
So... This sucks, and it's quite surprising, since it got a clean bill of health on it only a few months ago.
Anyway, I'll let you all know what they find.
 

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Still Fighting "Check Gas Cap" & PO455 - Please Help

I posted months ago that my 2006 G6 GT stereo was displaying "check gas cap." It escalated to the Check Engine Light, throwing code PO455 shortly thereafter.
I purchased a new gas cap at AutoZone and tried that for a while. It didn't work.
I purchase another new gas cap from the dealer and tried that for a while. We kept resetting the code, and kept getting the same code & notification back.
I took it to a local AAMCO. It's a long, expensive story. I'll fast-forward to what matters...
I finally got them to smoke test the car two weeks ago. They said smoke was pouring out of the valve cover.
I replaced the valve cover, pcv elbow, and valve cover gasket.
I've now got over $600 invested in this repair.
When I went to pick up the car, the actual mechanic took me aside and said if I get the message again, it's my gas cap.
I was surprised and I thought it was odd for him to pull me aside to tell me that, because I thought after all of this, I should not get the message again. Right?
He also told me he smoked the car and there is absolutely no evap leak left to be found.
I drove less than one mile away from AAMCO and... "ding-ding-ding"... CHECK GAS CAP.
Three or four days later, I've got the check engine light back on.
I haven't checked, but we all know it's got to be throwing PO455 again.
I would rush it back to AAMCO, except I had a virtual BATTLE with those people that lasted a good couple of months, involved corporate, etc., and at this point I'd rather avoid them, except they obviously didn't fix the problem again.
Basically, I'm not sure what to do.
I'm wondering at this point, based on reading a lot of posts here, if this is just something screwy in the computer system that just won't reset itself and go away, no matter what I do?
If anyone has any thoughts or advice, please help.
Thank you.
 

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I posted months ago that my 2006 G6 GT stereo was displaying "check gas cap." It escalated to the Check Engine Light, throwing code PO455 shortly thereafter.
I purchased a new gas cap at AutoZone and tried that for a while. It didn't work.
I purchase another new gas cap from the dealer and tried that for a while. We kept resetting the code, and kept getting the same code & notification back.
I took it to a local AAMCO. It's a long, expensive story. I'll fast-forward to what matters...
I finally got them to smoke test the car two weeks ago. They said smoke was pouring out of the valve cover.
I replaced the valve cover, pcv elbow, and valve cover gasket.
I've now got over $600 invested in this repair.
When I went to pick up the car, the actual mechanic took me aside and said if I get the message again, it's my gas cap.
I was surprised and I thought it was odd for him to pull me aside to tell me that, because I thought after all of this, I should not get the message again. Right?
He also told me he smoked the car and there is absolutely no evap leak left to be found.
I drove less than one mile away from AAMCO and... "ding-ding-ding"... CHECK GAS CAP.
Three or four days later, I've got the check engine light back on.
I haven't checked, but we all know it's got to be throwing PO455 again.
I would rush it back to AAMCO, except I had a virtual BATTLE with those people that lasted a good couple of months, involved corporate, etc., and at this point I'd rather avoid them, except they obviously didn't fix the problem again.
Basically, I'm not sure what to do.
I'm wondering at this point, based on reading a lot of posts here, if this is just something screwy in the computer system that just won't reset itself and go away, no matter what I do?
If anyone has any thoughts or advice, please help.
Thank you.
JennyA,

I’m sorry you continue to experience this problem. Another possible cause for this code is a damaged wiring harness or a cracked / leak in the EVAP canister. These are just suggestions and are not meant as a diagnosis.

I recommend consulting with a certified technician for additional assistance. They should be able to offer an official diagnosis and repair option(s).

If you need assistance locating a technician near you, please PM me your zip code for a listing.

Louis
GM Customer Service
 
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