Just to clarify there are moving parts mostly diaphragms and one vacuum switching valve. Do you happen to know what the code number or code numbers were that caused the check engine light come on? I can better advise you if I have the exact code numbers. Is it possible that they misdiagnosed the problem, you bet YA! Drivability and emission control problems are the most misdiagnosed parts replaced at your expense type of repairs that I run into.
Well unfortunately this one is a no-brainer for the dealership. I was kind of hoping you were not going to tell me it was these codes. In 2005 and 2006 there was a technical service bulletin number EG025-06 that deals with all of these codes. The problem is in fact in the charcoal canister and is related to the vacuum pump that was introduced into the system. The EPA mandated that all emission control systems have a five-hour off evaporative emissions system test done automatically. This vacuum pump built into the charcoal canister designed to run that test while the car has been shut off. The problem is the vacuum pumps go bad. I would try and see if you can get some assistance on the part from the dealer but don't hold your breath these all go bad on these years. If you want to try and buy the canister online for wholesale prices go to www.MetroToyotapartsnow.com I wish I had better news for you but unfortunately even their lube tech could diagnosed this one.