Thanks alot for the info, when the part comes in i'll give it a go on replacing it myself...great write-up, sounds pretty simple, thanks again!

 

Matt -

Are you talking about part #33 in this drawing?



Does it have an electrical connector on it?

 

Yup, part #33. It has an electrical connector and a hose going to it.

 

What did they do to end up fixing this?

 

I have this problem too.

I tried the replace gas cap ... but the CEL is on and the check fuel cap message came back. I know it's not the gas cap.

I'm going to pull the trouble codes this afternoon, but without the emissions system test equipment I guess its going to the dealership.

 

put the EVAP vent valve on. Part #33 in the picture above. Its cheaper to guess and put the valve on yourself, than to pay for a dealer to diagnose it. I'm a GM World Class technician and I see these problems all the time. Unless you have something really crazy going on, its usually the valve.

Pull the code and post what you got to make sure.

 

LOL...I've been sitting with this problem for a while now as well. Heading out to the car to manually start it ahead of time sucks donkey *****. I need to get the vent myself and just do it.

However, the dealer DID fix something like this for me before, under warranty. Is something like this likely to fail so fast afterwards? Maybe a year?


EDIT: I guess if '07-'08's can have this problem so soon, I suppose the replacement could fail just as quickly.

 

Got my new part and installed it a few minutes ago - takes about 10 minutes. I stripped the threads on the mounting bracket (thin metal and had rust) so I will have to throw a nut and bolt in it this weekend.

Looking at the old part, there are two components, the valve and a cup that has a filter in it.

Looks like the valve can be opened or closed to vent the system. So if the bcm calls out to it to close the valve to hold vacuum and it does not you get a "fail" and then the light.

Then why couldn't we just plug the line, or is it the electronics that fail to reply to the bcm? Is this part a sensor also?

Not really following the "importance" of keeping the system closed all the time, enough to throw a light. And is this valve the only way the tank would equalize pressure?

 

because gas evaporating cause green house gas.

 

Yippee. Going green with the V8.

 

Yeah - maybe I didn't make my point. The valve is a vent for the fuel system, either to let fresh air in, or to let vapor out. I don't know, maybe it does both.

The round part has a black coarse filter, in the center of it is a hole, which leads to the valve. The valve leads to a hose that leads to P/N 15, which is a $250ish part of the EVAP system.

If I said whats the purpose of drawing a vacuum in the system, when the valve is obviously a vent anyway?

If we all plugged the valve, the system would hold vacuum, and the computer would be happy.

But if this valve was plugged, how else would the fuel system breath, through the gas cap?

Sorry if anyone here designed that system, seems like the valve IS just a "feel good about the environment" part. At least it's cheap to replace yearly and about as easy to change as a fuel filter.

 

P0455 - Evaporative Emission System Leak Detected (gross leak/no flow)

I also had excessive oil consumption which makes me believe that it could be PCV related.

I haven't noticed any oil leaks or spots under the car. But it was defiantly low and burnt

 

Same code here...455. Same oil consumption, too...but it's unrelated. Some guys have considered installing a catch can to retrieve some of this missing oil...but I just top it off and get used to it.

 

I have my Monte in the shop now. They changed out my valve as well, also got a new battery, and drivers seat track, it was grinding abit. I am also trying to get them to change my seat cover the leather is wearing pretty bad. But it dosent look like they will do it, at least that's what the service writer said. So looks like I'm gunna have to talk to the service manager. I've had it in atleast 5 times for the seatbelt light, was in for that this time also!

 

has anyone posted a writeup for replacing the valve? I can at least try that myself before taking it in for the full evap test


SORRY - I didn't see the post earlier in this thread

 

Way to go Matt!!!

No light - 1st time in a year and 1/2!!!

Thanks!