What is this part?

[jd black]

Hi guys I was crawling around rewiring my tag lights after having a lot of problems with my wiring harness. Turned out it was just the damn amber light on the passenger side. I had a short. Curious to what this part is what does it do and this way if anybody knows a part number it's on a 2004 X XE model 1.4 l this way I'll know what to do and what to research. Thank you

 

[jd black]

 

[Peacemkr45]

From ClubXterra.org:
That’s not a canister, that’s a water separator for your canister. Either way if it’s leaking fuel then your canister is full of gas. I’d probably have to look at work because this is uncommon but on most Nissans, the valve that prevents overfilling and saturation is inside the fuel tank