Conquering the (NNBS) P0449 Code

My wife’s 2008 Yukon (5.3 Flex) threw the P0449 code a few weeks ago. I first checked the gas cap condition/tightness and cleared the code with my scanner. Within minutes the code was back and I knew I was in for more than a simple twist ‘o the gas cap fix.

First up was the” Evaporative Emission Canister Purge Solenoid Valve”
AC Delco Part #: 214-1680.
Purchased this from a dealership for $31.00


This installed alongside the driver’s side fuel rail. Once installed, I cleared the code and was good go to……for about a week when the P0449 came creeping back.

Up next was the “revised EVAP canister vent solenoid valve (CVS) assembly and jumper harness.”
AC Delco Part #: 20995472


AC Delco Part #: 19257603


Purchased from Amazon for $40 and $15 respectively.
To access the old CVS, I backed the Yukon up on Rhino Ramps and placed jack stands in place as a precaution. I then lowered and removed the spare tire in order to reach the CVS and associated piping (hard line to EVAP canister and vent hose running up fuel filler hose. Hooked everything up, checked and cleared the code before replacing spare tire.

It’s been about three code free weeks so I’m pretty confident the CVS and jumper took care of it. I used the following as a guide:

TECHNICAL
Bulletin No.: 09-06-04-28C

Good Job.

How many miles on the truck?

Sticky?

Thanks. 91K.

I did all the above when my 07 threw that code and none of them fixed it. I finally took it to the dealership for them to look at and within a few minutes of them pulling it back there the service manager called me and told me he found a corroded wire that broke inside the harness under the driver side floor board. This broken wire provides a constant 12v to the vent solenoid and the ecu supplies the negative when the solenoid needs to be turned on. He said it is a pretty common problem and he has seen it quite a few times. There is another member on this board that I know had the same problem. Hopefully this thread will help others troubleshoot in the future.

Gtk thanks

Most Hated what did the dealer do to fix this problem. My 07 tahoe is throwing same code and have replace all but purge canister on fuel rail. I just posted about trying to get help.

Read post 4

What I was meaning did they install a new wire or just repair the corroded wire? Wonder if this the same problem as I have and how could I find it? Or just carry it to dealer. Which I do not want to do.

Keep us posted on your progress if you do decide to get this checked into at a dealership, Swampfarmer! We're available to assist as much as possible to make sure this issue is resolved.

Sarah (Assisting Jennifer)
GM Customer Care

GM Customer Service said:

Keep us posted on your progress if you do decide to get this checked into at a dealership, Swampfarmer! We're available to assist as much as possible to make sure this issue is resolved.

Sarah (Assisting Jennifer)
GM Customer Care

Click to expand...

What I want to know, is why you guys don't just get your own usernames! For crying out loud, they are free! You have four or 5 people posting under Louis's account.

Anyway, I just ordered the exact same parts from Amazon today, but I have a P0446 code. Pretty sure it's related. I'll have to check on the broken wire though.