Engine Light - Code: Po0440

[garnaout]

Hello guys,

so I'm not a good mechanic and thought I would post this here before going to see a mechanic and spend a fortune.

I have an engine light with my 2000 MR2 the code is PO0440 and PO0440 P (whatever the difference is) which I know it's EVAP.  Gas cap is tight however I do see a lot of dirt around it from gas - obviously something wrong is going on there.  Other than that, absolutely no symptoms.

Is it something I can do it myself?