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Discussion Starter #1
Just recently had my check engine light come on for P0449.

At the time the CEL came on, my EVAP Purge Valve was constantly actuating at idle, so I replaced that first. (See picture)

162306


I cleared the CEL and reset the computer by disconnecting the negative battery cable for several minutes and the second time i started the car after this, the CEL came back on for the same code.

Now I am onto replacing the Vent Valve Solenoid (see picture), however I am not sure where it is located. After looking up under the rear end of the car for a while I came to the conclusion that it is on top of the fuel tank and I'm not too excited to drop that and replace the solenoid.

162307


I have also ordered a new fuel cap as I read that it could also be the source of the code, although I'm doubtful that it is.

If anyone has had experience replacing the Vent Valve Solenoid, please let me know where it's at and how big of a hassle it was to replace (I do have the capability and tools to do 95% of all automotive maintenance jobs). Or if you have had the same code and the Vent Valve Solenoid was not the source of the problem, let me know what did solve your issue.

Again, this is on a 2016 Impala, new body style. I've found a lot of info on replacing these parts on the previous generation Impalas, but very little on the most recent generation.
 

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3.6? Iirc, it's mounted inside the fuel filler door on the frame/bracket? P0449= vent valve/solenoid circuit malfunction.
 

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Sorry, no pics. Jack up lr and look up inside lr 1/4 panel. That's the location on my son's '16 Limited (old body style).
 

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Discussion Starter #5
Sorry, no pics. Jack up lr and look up inside lr 1/4 panel. That's the location on my son's '16 Limited (old body style).
Again, this is a 2016 NEW BODY STYLE.

The fuel door is on the opposite side of the car, and when looking up in the quarter panel, there is only the fuel filler neck and breather pipe.
 

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Discussion Starter #6
Looking at this diagram that I found, it (Item 3, Solenoid Valve) looks like it's on the side of the Vapor Canister. I remember seeing this canister yesterday when I was up underneath the car looking for the solenoid. Unfortunately it looks like I'll need to drop the tank to get to it.
162308
 

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Looking at this diagram that I found, it (Item 3, Solenoid Valve) looks like it's on the side of the Vapor Canister. I remember seeing this canister yesterday when I was up underneath the car looking for the solenoid. Unfortunately it looks like I'll need to drop the tank to get to it.
<snip pic>
The on-line Chilton's calls for dropping the tank. I'd say that's confirmed.

Doug

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Discussion Starter #9
The on-line Chilton's calls for dropping the tank. I'd say that's confirmed.

Doug

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Yup. Posted a similar thread on FB to the Impala Group and a GM Employee contacted me and told me that the tank needs dropped. Luckily he had access to their repair manuals and was able to send me the instructions. ??

Is the on-line Chilton manual complete for the new body style Impalas? I know you and I were talking on a separate thread about the Haynes hard-copy manual not being complete yet.
 

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Is the on-line Chilton manual complete for the new body style Impalas? I know you and I were talking on a separate thread about the Haynes hard-copy manual not being complete yet.
It's lacking. And lagging. The newer the car, the less info there is. Generally speaking, I'd say the info is good on anything 2-3 years old, but kinda sketchy on newer cars.

That said, I access the Chilton's info via the Plano library website, so I'm not paying for it (at least not directly). The one subscription I have purchased (thus far) is from Alldata for my daughter's 2013 Ford Escape, and it seems reasonably complete.

As for Haynes versus Chilton, keep in mind they are the same company. I have both hardcopy manuals for my gen1 Chevy Cruzes, and the content is about the same.

What I saw of the on-line Chilton's info for the newest gen Impalas seemed fairly robust. It has a pretty klunky interface that makes me think they need to take some time to review how they present/organize their data, but once I got to the data, it seemed pretty complete.

Doug

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Discussion Starter #11
Just a head's up for anyone with the same issue, a new fuel cap does not fix this issue. I just replaced it and cleared the code. As soon as I started the car again the code came back.
 

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Just recently had my check engine light come on for P0449.

At the time the CEL came on, my EVAP Purge Valve was constantly actuating at idle, so I replaced that first. (See picture)

View attachment 162306

I cleared the CEL and reset the computer by disconnecting the negative battery cable for several minutes and the second time i started the car after this, the CEL came back on for the same code.

Now I am onto replacing the Vent Valve Solenoid (see picture), however I am not sure where it is located. After looking up under the rear end of the car for a while I came to the conclusion that it is on top of the fuel tank and I'm not too excited to drop that and replace the solenoid.

View attachment 162307

I have also ordered a new fuel cap as I read that it could also be the source of the code, although I'm doubtful that it is.

If anyone has had experience replacing the Vent Valve Solenoid, please let me know where it's at and how big of a hassle it was to replace (I do have the capability and tools to do 95% of all automotive maintenance jobs). Or if you have had the same code and the Vent Valve Solenoid was not the source of the problem, let me know what did solve your issue.

Again, this is on a 2016 Impala, new body style. I've found a lot of info on replacing these parts on the previous generation Impalas, but very little on the most recent generation.
Stop replacing parts in hopes it'll be the "thing".... Run a smoke test on it to see where it is leaking.
 

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Discussion Starter #13
Stop replacing parts in hopes it'll be the "thing".... Run a smoke test on it to see where it is leaking.
With this EVAP system it may not be a leak. It's probably this solenoid not actuating properly which is all within a closed system.

And the guy that I was in contact with who works at GM informed me that this is what is listed as the part to replace for this code.
 

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Discussion Starter #15
New development:

Yesterday I started my Impala and it immediately idled very rough. My "Service Stabilitrak" warning came on and my CEL began flashing.

After about 15-20 seconds the idle smoothed out to normal and the Stabilitrak warning went away. I pulled the car into the garage from the street and read the codes and in addition to the P0449 code, I found a P0300 code for Misfire. I cleared the codes since it was running normally and took it for a drive. I ran it up to 80 mph and everything felt fine.

I have a separate thread for this P0300 code, but since this thread has had more attention, I'm deciding to bring it up as a side note as I'm curious if this misfire could be caused by the bad Vent Solenoid.

I find it odd that this isn't a consistent problem, as I've started the car about 6-8 times since then and have had no issues, just the P0449 code.

Thoughts?
 

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Discussion Starter #16
Another Update:

I've had the vehicle into the dealership to get the code checked out and after about two hours of diagnostic testing, they told me that the Vent Valve Solenoid still appears to be bad. They connected their HMI up to the vehicle, confirmed that they had power to the solenoid, but when trying to actuate it, nothing.

$288 later, nothing has been resolved. They offered to change the solenoid again for $240, and if that didn't fix the problem, they wouldn't charge me the $240.

I'm not sure if I should just do it, or buy another solenoid and test to see if it works myself.
 
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