Check Engine Light
02-02-2009, 09:50 AM
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Check Engine Light My engine light kept turning on becasue of my gas cap. So I baught a new gas cap reset my engine light and everything was good for about a month and a half then yesturday it said check gas cap and now today the stupid engine light is on again. Any suggestions
02-02-2009, 02:49 PM
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02-02-2009, 03:49 PM
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02-02-2009, 07:29 PM
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My light has been on for the past year or so, major evaporative leak. Thought it was the 420.
Changed the gas cap, no. Badd had to replace his filler neck.
I would have figured the light would have burned out by now ... but taxes will fix it.
Changed the gas cap, no. Badd had to replace his filler neck.
I would have figured the light would have burned out by now ... but taxes will fix it.
02-03-2009, 07:08 AM
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Thats honestly what I'm affraid it might be. It can't be cheap to replace the whole filler neck. Is there anyway to just turn that sensor off with a predator or something like that?
02-03-2009, 08:24 AM
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Thought Badd's was under warranty. Doesn't look too bad to replace, like 4 screws. The other part may be the canister which was $271, bolted to the gas tank. The rest of the parts are some plumbing.
Think I read that they need to do a smoke test to find the leak. I'll probably pay for that instead of replacing a bunch of parts blindly, as it will be a while before its nice enough here to lay under the car and inspect it.
Think I read that they need to do a smoke test to find the leak. I'll probably pay for that instead of replacing a bunch of parts blindly, as it will be a while before its nice enough here to lay under the car and inspect it.
02-10-2009, 09:12 PM
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Vent Solonoid Had the gas cap message a few times. Then the check engine light. Went to dealer. It was the vent solenoid, probably the one mentioned above. it sits up in the drivers rear wheel well. They changed it and haven't had a problem since.
Basically, the computer needs to see a certain pressure rise in the gas tank a certain amount of time after the engine is shutdown. If it doesn't see the required rise you get the gas cap message or if it's bad enough, the check engine light.
Basically, the computer needs to see a certain pressure rise in the gas tank a certain amount of time after the engine is shutdown. If it doesn't see the required rise you get the gas cap message or if it's bad enough, the check engine light.
02-12-2009, 09:33 PM
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The gas cap message is just an idiot light saying your EVAP system has a large leak. A vent valve that wont close is also a large leak. Its super easy to replace on a lot of these cars too. On an Impala, it only takes a flashlight and a flat blade screwdriver.
04-19-2009, 07:02 AM
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Just had the "check gas cap" message appear last night on my way home. Havent driven it yet today to see if it triggers the check engine light. Not sure if it's because of my downpipe or if it is the EVAP vent code mentioned above. I can get the valve from gmpartsdirect for pretty cheap if it is the valve, just wondering if its easy to replace myself on a GXP or if I should just take it in and pay the labor? Thanks.
04-19-2009, 09:16 AM
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99% of the time on the cars that are '07 and older, its the EVAP Vent valve. Its really easy to replace. Like I said above all you need is a flat blade screwdriver and a flashlight. You will also need pliers to take off the hose to the valve. If you lay underneath your car behind the LR tire, its mounted by the fuel filler neck inside the LR quarter panel. You have to use the screwdriver to bend a little tab and then the valve slides off the mounting bracket. Remove the hose and connector and transfer over to new valve. Bend the tab back on the bracket and the valve just slides back on making a click noise when its fully seated in the bracket.