Toyota Repair: ccv and charcoal canister, charcoal canister, fuel vapors

Question
They did replace the CCV at my expense.  Did the TSB say the CCV might fail or that the charcoal canister might fail and end up clogging the CCV?  The check engine light did go off after the CCV replacement; that's one of the reasons they advised that we not look into replacing the charcoal canister.  Plus they weren't sure if the thing clogging the CCV came from the canister.

The service adviser told me the canister was at the rear near the gas tank and he wasn't sure if the tank needed to be removed to get to it.  I looked up the vacuum diagram on Mitchell On-Demand at the library and that figure does show a big box that is rear of the gas tank called a charcoal canister.  The reason they think there is something in the vent line is because the volume of vapor was not high so they thought something was restricting it.  There were no other codes.
-------------------------
Followup To
Question -
I have a 2001 V6 Camry.  The check engine light came on.  The dealer found code P0446 stored in ECM.  They checked the fuel evap. system and found the CCV valve stuck closed (plugged with something that they think might have come from the charcoal canister).  They replaced the CCV valve but there was still a slight restriction from canister hose that goes to the rear of vehicle.  They didn't see anything on the CCV side of the fuel hose.  They advised that since they could reset the computer and they would have to drop the gas tank to get to the charcoal canister ($$$) to see if this takes care of the problem, even though the car may not be as fast since there is less flow of vapor.

Could you tell me how I might take care of this problem myself?  Would I have to remove the gas tank to get to the charcoal canister?  (I always thought these were in the engine.)  If so, do I need to empty the tank of fuel and be concerned about fuel vapors?  Should I then try to blow out the fuel hose line with air?  I'm just guessing on what to do, please let me know what to do step-by-step.  Thanks.
Answer -
Hello Tony, welcome to my expert page.
I believe there was a service bulletin issued regarding this ecu code and the remedy is to replace the CCV, was this done under warranty or at your expense?
Did the check engine light go off after the valve was replaced?
They have to clear the DTC, it's part of the repair.
I'm a little confused about what they are recommending because the eveap canister is located either in the engine compartment or it may be located next to the gastank in the rear, I have never found it necessary to remove the tank to replace the canister and I'm not sure this is the problem, if the light was reset and did not come back on the system is functioning and your driveability problem may be something else, a leaking canister does not cause performance problems neither does a clogged vent line to the canister.
By the way, were there any other codes besides the 446?
I can reply until 8pm PST,Friday and after 5pm Sunday.  

Answer
The tsb does not specify the canister as the source of the problem,I do not have the tsb here so I can't give a specific answer, all I know is that every ccv valve I replaced fixed the problem, toyota has also extended the warranty period for some of the canister problems, it may be a good idea to call their 800 customer service number and give them all the information you can and they may be able to help and you may be able to get this taken care of at no charge. That is, if the evap canister is the real problem.