# Carbon Canister/Vent Control Valve



## bowl3001999 (Sep 26, 2006)

Ok, I don't know much about the mechanic of cars (ok, I don't know a thing!) My husband has a Frontier and it has 55,000 miles on it. The "check engine" light came on and I took it to the dealer. He said that the carbon canister and vent control valve need to be replaced (to the tune of $650!) He said it was unusual for this to happen at lower miles...anyway, the light went out. Someone at my husband's work told him that it probably doesn't need replaced, that it was the sensor. I called the dealership and they said "yes, it does need to be replaced, and there is no way it can be looked at to tell that". "The computer stored a code and maybe it reset itself, and the light will probably come back on". I just need to know if anyone can help me here...do I really need to replace these things? Thanks! Wendy


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## Centurion (Sep 5, 2002)

If the carbon in the canister gets saturated with liquid gas (as opposed to vapor) then it needs to be replaced. So the dealer is saying that the valve malfunctioned and allowed liquid gas to flood the canister. It sounds plausible. I don't know what the alternative is to paying the $650. If it was me I'd get a junkyard canister and vent control valve, but it doesn't sound like you would want to traipse through a junkyard.


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## bowl3001999 (Sep 26, 2006)

bowl3001999 said:


> Ok, I don't know much about the mechanic of cars (ok, I don't know a thing!) My husband has a Frontier and it has 55,000 miles on it. The "check engine" light came on and I took it to the dealer. He said that the carbon canister and vent control valve need to be replaced (to the tune of $650!) He said it was unusual for this to happen at lower miles...anyway, the light went out. Someone at my husband's work told him that it probably doesn't need replaced, that it was the sensor. I called the dealership and they said "yes, it does need to be replaced, and there is no way it can be looked at to tell that". "The computer stored a code and maybe it reset itself, and the light will probably come back on". I just need to know if anyone can help me here...do I really need to replace these things? Thanks! Wendy


I should also add that my husband said my son was playing with the gas cap and has never filled up the tank all summer...the light came on right after he did that.


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## dvdswanson (Nov 6, 2005)

FWIW, on OBDII systems not putting the gas cap on completely (at least 3 clicks heard) can cause an evap code to be set.


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## msubullyfan (Jul 24, 2005)

The price you're being quoted seems unreasonable to me. I'd look elsewhere for a repair (including a reputable mechanic that is NOT a Nissan dealer if you only have one in your general area to take it to).


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## bowl3001999 (Sep 26, 2006)

*Thanks*

Thanks so much for the feedback...about not putting the gas cap on tight...that is exactly what a friend of my husband's told him. I guess we'll have to prove the dealer wrong when the "service engine soon" light never comes back on.


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## azrocketman (Oct 5, 2005)

bowl3001999 said:


> Thanks so much for the feedback...about not putting the gas cap on tight...that is exactly what a friend of my husband's told him. I guess we'll have to prove the dealer wrong when the "service engine soon" light never comes back on.


At the mileage you quoted the system was probably still under the emissions warranty. The emission warranty generally runs longer than the vehicle warranty. I'd question my trust in this dealer.

Steve


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## bowl3001999 (Sep 26, 2006)

azrocketman said:


> At the mileage you quoted the system was probably still under the emissions warranty. The emission warranty generally runs longer than the vehicle warranty. I'd question my trust in this dealer.
> 
> Steve


I can't find it anywhere online (about the warranty)...I actually can't wait for the dealer to call me back (the part is on backorder.) The light still has not come on and I found an interesting article after reading a reply that a sensor could be tripped by not tightening the gas cap. I'd like to hear what they say when I tell them the light is still not on and tell him what #2 says!

This is especially interesting:

*There are two ways to turn off the check engine light.


A repair technician can do so once repairs have been made.
The OBD II can automatically turn it off when it fails to detect the problem after several diagnostic cycles.
*
Dealing with your car's check engine light


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## msubullyfan (Jul 24, 2005)

I'd be careful about getting too snippy with the dealer -- especially if I didn't know enough about cars to speak competently about the problem (which you admitted in your first post). If you don't know exactly what the dealer told you (it certainly isn't clear from your first post exactly what the problem was and exactly how the technician diagnosed the problem), something may be getting lost in transmission to us. And, that info in your last post doesn't really tell us anything. 

If there is a faulty vent valve, it will likely make the CEL come back on -- but it may be weeks or months before it does it again. If you act too critical to the dealer about the light going off and it comes back on later... well, I'm sure you'll feel a bit embarrassed to take it back down to the dealer.

Sometimes the CEL is something that will go away by itself, and it may indicate a very minor problem. More often than not -- it isn't that easy.

Dealer repairs are expensive, but contrary to what a lot of people seem to think, there are very few disreputable dealer repair departments out there. Even if the gas cap was what caused the CEL to come on, the dealer may have investigated and found the carbon canister and vent valve to be faulty.


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## bowl3001999 (Sep 26, 2006)

msubullyfan said:


> I'd be careful about getting too snippy with the dealer -- especially if I didn't know enough about cars to speak competently about the problem (which you admitted in your first post).


Well, I'm certainly not going to get rude with the dealer. I'm just going to state the things that I know and see what happens. And, I'd rather not take it to a dealer because they always overcharge you. I'd like to find a reputable shop in my area...since it's out of warranty and there's no need to go to the dealer. I'm really just going to mention that a few people have told us that a code can be tripped by not closing the gas cap all the way.


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