My buddy had the same issue on his 2000 Corolla. He needed the VSV or vacuum switching valve next to the vapor canister. The local parts guy stated that this is a fairly common problem.
Same here. Had a P0441 code, (found out by failing inspection) got a Vacuum Switching Valve ,VSV, for $80 at Toyota Dealship and I was able to clear the light and zip right through inspection. Glad I didn't buy a charcoal canaster for $350. I found these instructions on another post and they worked like a charm.
Vacuum Switching Valve (VSV) - Codes P0440, P0441, P0446
There are two VSVs. One is up at the air cleaner (according to my dealer this one almost never fails) the other one (the one that does fail - wouldn't you know it) is down underneath the car beside the gas tank, and adjacent to the charcoal canister. Presumably it fails because it is more exposed to splash from the road. One clue that it is a problematic VSV is that the above 3 codes appear at the same time. This problem does not affect vehicle driveability, although it might be a problem when you go for your emissions test. Replacing this valve is not hard but it is uncomfortable because you're lying on your back looking up at the VSV (unless of course you have a hoist - which I don't) and dirt is falling on your face. You just have to pull off a short (few inches) length of tubing which obstructs access to the VSV. This tube is not clamped, you just pull it off, it is a larger diameter with a small tube branching off. Once you have pulled that off, you have a better view of the VSV. It is held by one Phillips screw, which is hard to get at. You would need a right-angle screwdriver; I don't, so I just managed to get it off by grabbing it with a pair of pliers, and turning it bit by bit. Narrow vice-grips would be good too. Feel free to do much cursing while attempting to remove screw. When the screw is removed, undo the electrical connector, and pull off the two tubes from the valve. Out with the bad, and in with the good. In my opinion the VSV is held quite firmly by the attached hoses and electrical connector. I didn't try to get that screw back in, it is just not worth the effort. You could use a cable tie to secure the VSV quite well. Reset your CEL and congratulate yourself.