# check engine light



## Lukemo2 (Apr 13, 2010)

Check engine light came on today in my '04. I took it to Advanced Auto and the code is for an evaporation leak. 

The guy said it could be something as simple as my gas cap not being on tight enough. 

Took the gas cap off and put it back on. Engine light is still on. But, I don't know if it would go off even if that was the problem and I had fixed it by doing that. I probably should have asked the dude at Advanced Auto to clear the code for me, huh?

Any other thoughts on what it could be?

Thanks,

Luke


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## cmack111 (Feb 25, 2011)

What is the exact code?

If the code was for an EVAP leak than you need to smoke the system to find the problem. 

It could be the gas cap, but it could be alot of other things as well. 

Good news is that it will not affect the way the car runs. It is strictly an emissions control problem.


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## Falco21 (May 11, 2010)

999 times out of 1000 it's the gas cap.

It might take a few times filling up before it turns itself off. You could also have them clear the code. As long as it is not flashing, you're fine. That light will come on with a leak the size of a pin hole.


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## HP11 (Apr 11, 2009)

If it is the gas cap, there is a recall. Look it up. GM will actually give you one free if you wish to hassle with them. It's an under $10 part at Autozone, etc.


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## Lukemo2 (Apr 13, 2010)

cmack111 said:


> What is the exact code?
> 
> If the code was for an EVAP leak than you need to smoke the system to find the problem.
> 
> ...


I don't know what the exact code is. The guy at autozone wasn't very friendly and I really didn't feel like talking to him any more than I had to. He just told me what the problem was and offered the gas cap as probable cause.

Yeah, the car isn't running funny or anything. I just hate that the light is on. I'll probably stop by there again and ask them to clear it for me.

Thanks to everyone for their thoughts!


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## bills_zpam (Sep 22, 2011)

Falco21 said:


> 999 times out of 1000 it's the gas cap.


Well said. Check the gas cap, clear the codes, and worry about it if it comes back. You can get an ODBII reader for like $50 - it's been standard since like 1998. It saves a lot of headaches.


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## nick_atooo (Dec 28, 2010)

I had that code come up a few months ago. The garage that checked the code offered to Chase the leak for $120.00. I said no thanks, disconnected the battery and twisted the gas cap while slightly pulling upwards on the cap. Light went off and has not come back on. Every time I fill up I replace the cap as stated above. The mechanic also said there was no way it was my cap, the search function on either this forum or ls1 gto saved me a few bucks!


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## svede1212 (Nov 1, 2005)

nick_atooo said:


> I had that code come up a few months ago. The garage that checked the code offered to Chase the leak for $120.00. I said no thanks, disconnected the battery and twisted the gas cap while slightly pulling upwards on the cap. Light went off and has not come back on. Every time I fill up I replace the cap as stated above. The mechanic also said there was no way it was my cap, the search function on either this forum or ls1 gto saved me a few bucks!


He's got the idea. Pull the negative battery cable off to reset the code.


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## HP11 (Apr 11, 2009)

However, if you have pull up on the cap to remove maybe it needs to be replaced. I just twist mine and I haven't had any problems in the 2½ I've owned mine.....


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## GTO JUDGE (May 14, 2005)

As HP mentioned..... The gas caps are warranted for 10 years. They have not been recalled but they are covered for replacement, I am on my 4th. Call your former Pontiac dealer and inquire.

First time mine acted up it threw a code and it was reset, the other 3 times it did not throw a code but the cap wouldn't ratchet down.... I'd suggest: Every time you visit your friendly refilling station pay attention to the operation on the cap see if will lift off without unscrewing. After you reinstall it after fill up and you think its secure, give it a little wiggle to see if it will come off. Make this a habit. Some have had no issues while others like me have had multiple replacements.

If your former dealer has no idea what you are talking about tell them all owners of these cars for 2004-2005 cars had letters sent to them, I don't know if 2006 owners had this mailed to them.


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## OmikronPhi (Jul 24, 2009)

When refilling, DO NOT push down on the gas cap while twisting it back on. It should reset on its own after a few fill-ups/start cycles. If it doesn't reset on its own, take the negative bettery terminal off. If it comes on again then go to an auto parts store that has the reader, read the code, write it down, and search the code. I had this trouble code and it showed up a large leak in the evap system...reset the code, had it come back; searched the forums and found out the gas cap "DO NOT push down while tightening" thing...haven't had it come on since...Hope this helps!


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