Heya, I have a 2005 Chevy 2500HD with the 6.0 Vortec in it. A few days ago, the SES light flipped and spit out the error code P04406 when I scanned it. I have found a few good threads on this forum regarding possible causes and fixes for this code. I would like to try and clean the valve rather than replacing it. I am still a little confused as to the actual location of the vent valve I am looking for. I located a small canister on the read of the gas tank, held on by a sliding clip. After taking this canister off, I removed the solenoid attached to the side of it. This solenoid has 1 hose attachment and 1 electrical connector. I looks like this ( http://imgur.com/xbNkT ). Is this the solenoid for the vent valve that I need to clean, or do I need to follow the outgoing hose farther up and clean something else. Upon following the hose I found that it connects via a quick connector to an unknown black box. This black box also has 2 other hoses coming into it. I was able to remove the hose running from the canister to this box. Do I simply need to stick an air hose in there and clean it out? Or what else is it that I need to do to make that valve operate properly again? If you need any additional information from me just let me know. Thanks in advance.