Part ID and Question Please

[Jumanji]

Hey All Just wondering what exactly this is, I have the tube currently unplugged and for some reason when we plug it in it throws a check engine light? What does it do and is it important to have plugged in. Part is located near the top, windshield side of my engine bay.
https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-prn2/t1.0-9/1463895_10152368824783584_422584702763841112_n.jpg

[Baby Face]

that looks like just maybe.... the fuel filter.

does that hose thats unplugged go anyway? another cannister looking thing? ie charcoal cannister.
im guessing this is a 90's model civic/teg?

[Cartoon]

Yep that line goes to te charcoal canister. Might be a faulty sensor on the canister. Everything else plugged in for your evap?