P0446 Hummer H3 2006 Hi, I live in England and own a 2006 Hummer H3. I have the P0446 code, and changed the Vent solenoid for a new one (It is the same ACdelco part number) I just needed to remove a small electrical extension as the female electrical socket was not the same. I cleared the code and a day later the code P0446 was back. The car has only done 30000KM. I think I will have to blow out the pipework, check the electrical supply and make sure the new unit works. The problem is that there is only one Hummer dealer in the UK, and they are miles away, and that is why I have to do it myself. I have spent days searching the internet, and this site is much more informative than any others I have found. Has anyone got any other suggestions that I need to try whilst I am working on the vehicle. This is my first post, so hoping for some good information. regards from across the pond!