06 wrx here and i had the same problem last year. The pump, and both valves all had to be replaced. I got the P2444 code, and eventually the "valve stuck open" code which i can't remember. Luckily, it was replaced under warranty for me.
The next time it will fail, and i'm sure it will, i'll just get the block-off plates and have those codes supressed by my tuner... i doubt i'll be so luckly for another free replacement.
If you can't get it covered and want to save money, i sugges the block-off plates too. Also if you're worried about emissions, its true, that whole system is just for cold-start emissions so testing shouldn't be a problem.