Thanks for all the help guys! I just took it into the shop turned out to be the Fuel Pump! It was going bad, worst part is they told me the fuel pump has been replaced one time already!..... Oh well 500$ beats wasting time and money playing the guessing game all day in the heat!

 

Just an FYI. I had both codes P0449 and P0455. (2005 Silverado 2wd reg. cab) replaced the evap vent with the 06 suburban vent valve (ACdelco #214-2149) for a little over $20. Took less than 5 minutes. Light went off a couple days later.

 

I too am an owner of a 2008 Suburban that was producing the P0499 and P0455 codes.

When I first noticed the check engine light I used my OnStar service who gave me those exact error codes. I took the truck to the dealer and even though I told them the exact code numbers, the tech insisted that my wiring harness was being chapped under the engine and was producing a variety of errors. I was told the harness needed to be repaired at a cost of $376.00. I drove off with the check engine light off for about two hours then it reappeared. I again asked OnStar to check for errors and again they produced the same 0499 and 0455. I brought it back to the dealer
and I was finally told the vent solenoid was faulty. I then was charged a total of $222.82.

$99.50 for the labor, $73.32 for the Vent (20995472) $35.72 for the harness (19257603) plus tax. This totally looks like a scam by GM and as I read the other posts it appears that the placement of the vent is more the problem.

 

We are getting codes 0449 and 0455 on our 07 Burb. After reading the 17 helpful pages of posts I have decided to replace parts 20995472 and 19257603. GM Parts Direct has them for $37.39 and $18.12.

This video on youtube was really helpful too.

 

Do report back if it resolves your issue

 

Will do.

 

I dealt with the same problem. Had to replace the gas tank (cracked outlet nipples to fuel lines). Still got codes. Finally discovered while running it with the code reader on with my mechanic that a bad contact on the wiring harness right near the molex to the solenoid was the culprit. It would work and then cut out as we moved the wires.

 

Man, that bites that you did the other first. Was it under warranty or did you have to pay for all of that?

 

New guy question I have a 2010 Suburban and only getting the p0449 code I was looking up parts but not sure exactly which one to get any help would be greatly appreciated.

 

Something else to try is just having it cleared and see if it comes back.. It could have simply stuck at that particular test time and is functioning correctly now...
clear it and see if it comes back, then address it, if not drive on