just got the error po449 as well, it says- evaporative emition system vent valve solenoid circuit.
i saw on top the part from rockauto- awesome! do anybody knows where i can see it in ytube how to change it, or at least where it located?
cheers

 

 

Well, that unit doesn't look like small solenoid part.... I had removed it before when I was fixing my H3.

 

20941985 valve + 19257603 harness & reuse the hose, or spend more and get the 20907779 (with hose) + 19257603 harness
How to install valve:

 

 

Also.. judging on my own experience... when I took my h3 appart , I removed the evap control box to properly clean where it sit and rustproof it, so I had to disconnect all the tubes attached to unit. And I noticed that one of the steel tubes was rotten and totally cracked. So I cutter rotten psry and replace it with rubber high pressure one.
I don't remember the error code, but I remember I says "minor leak".
So dude, depends where the wehicke is, if its in North, you should check for corroded parts, like in mine...