Help! Advice Needed On Engine Problem

[mphil804]

I just got back from running a diagnostic on my 2000 Corolla. The check engine light went on the Sunday following my oil change on Friday. I didn't know what to make of it since my car sounded fine. Anyway, after running a diagnostic today, I got the following informations (as listed on the printout)

P0466

EVAP Emission

Control System

Vent Circuit Malf

From what I was told, this has something to do with the solenoid unit and it has the potential to cause problems for my engine, though it's not guaranteed to. Would this be covered at all under a powertrain warranty (which I have) or what could I expect for costs on repair in US dollars? I'm not even sure if this was a result of poor mechanic work on the oil change or if it's wear and tear or what - but I'm concerned about the price. And I did check the gascap : P Thanks for your help in advance!

[mphil804]

Bumped due to the emergency nature of the situation.