Conquering the (NNBS) P0449 Code

[CrashTestDummy]

Thanks. 91K.

That damn canister must have a timer on it so when it reaches about 90K miles on the truck, it switches into failure mode.

Same thing happened on my wife's truck, and I followed pretty much the same process you did. No fix until that canister and harness.

 

[rezapci]

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
View attachment 295194

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

Will Thank You for your input
Mine is 08 GMC Yukon 5.3 SLT that I have the same problem but no code! It take me about 10 min to fill up!!!

 

[gbleezy]

Thanks for this thread. My 2008 Tahoe 5.3 Flex with 145k miles threw up the P0449 code and replacing the canister vent valve finally fixed it.