MY 2006 CHEVY SILVRRADO W 4.8 HAS CHECK ENGINE LIGHT ON AND WHEN I PLUG IT UP I GET THIS CODE - PO449- ANY SUGGESTIONS TO WHAT IT MEANS?

Your Po449 code means: Evaporative Emission (EVAP) Vent Solenoid Control Circuit. Check to see if anything on you EVAP system has gotten disconnected and make sure that none of your hoses have gotten old and bridle or have holes. If everything looks ok, you probably have to replaced the Vent Solenoid Valve, which is located on the EVAP canister.

engine lights came on and the codes are po449 and po449p on a 2007 chevy avalanche

P0449 control vent valve/solenoid circuit malfunction, This code necessarilly deal with replacing the vent solenoid it about the circuit,the evap vent solenoid circuit may have rub through on the frame (located on the back of the fuel tank),it can also be the connector,the vent solenoid itself,or the connector

get a new gas cap your evap sytem isnt working if the gas cap doesnt work then you might have a leak and check your EVAP purge valaves

More than likely the evaporator vent valve.

p0449 is an evaporative emission code that indicates a problem with the canister vent solenoid.. without being able to scan and check all of the system I would recomend replacing the vent solenoid. I believe their was a GM TSB on that part and it has been modified.
please respond with fix details

There is a solenoid that open and closes with 12 volts, usually located close to the fuel filler tube area. This open to allow you to fill your tank, then closes after some inputs for the computer are satisfied, and then a pressure sensor verifies the system is working. First, make sure the cgas cap is tight, and if the light doesn't go away in a couple days of normal driving, get the solenoid checked.

Code po449 is the canister vent valve solenoid error.This is a common problem with these valves because they are under the truck in the rear by the spare tire and they get all the dirt and water and snow,if you live in an area where you get snow.You will find it on the canister under the vehicle by the spare tire.

your going to have to check online for that code and usually no matter what you can always drive a car with the check engine light on as long as the car feels fine.

CODE PO449 -EVAP VENT SYSTEM PERFORMANCE CONDITION.POSSIBLE CAUSES. VENT SOLENOID CONTROL CIRCUIT IS OPEN OR SHORTED TO GROUND OR.VENT SOLENOID CONTROL CIRCUIT IS SHORTED TO SYSTEM POWER B+.OR VENT SOLENOID POWER CIRCUIT IS OPEN TEST THE ENG 1 FUSE.OR VENT SOLENOID IS DAMAGE OR HAS FAILED.OR PCM HAS FAILED.