P0449 evap Selenoid and a dead battery?

[Skydmark]

Hey all, I've been researching the common P0449 code as the 06 Yukon I just got is throwing this code. If I clear it, it comes right back. So I'm suspecting the selenoid is bad especially living in the Northeast. Right now it's dark by the time I get out of work (and cold) and I don't have a garage so I'm planning to tackle as much as I can on saturday when it'll be a toasty 45 degrees, lol.

That being said I think I'm going to go ahead and order a vent selenoid so it's here and they're cheap enough and replace it. However, last night after sitting for 2 days I found the battery dead. It's a fairly new battery dated 2025.

Mostly I'm just trying to have a good game plan so my real question here is could the bad vent selenoid be causing a parasitic draw. As I understand it the vent is normally open and receives power at all times and the ecm grounds it out to close the vent. If the selenoid is shorting itself then it would be locked closed? And would this cause a parasitic draw that's killing my battery?

Thanks in advance!

 

[Skydmark]

Well after doing some more research, I came back and was going to delete this thread but I don't see I can do that so instead I'll just say it's much more likely that These are two seperate problems.

Especially considering I have the Bose sound system and the amp is a common known issue. So looks like I'll be testing current draw and voltage drops. I'll start with the sounds system and instrument cluster and see where I get.