Toyota Repair Problems? Ask a Mechanic for Answers ASAP
With all due respect information above is not correct the warranty on this charcoal canister is only three years and 36,000 miles. The problem is not likely in the charcoal canister even. They do not get clogged. If you have both of these codes listed at the same time the 446 code may be a false code due to the evaporative system not passing the self test due to a leak which is the 440 code. The fuel filler neck is very common to corrode at the gas seal or if the gas cap is even slightly loose it will set both of these codes. The other problem that we see especially if you live in the Northeast where there is corrosion, the vacuum switching valve that is mounted to the charcoal canister goes bad. This will set the 446 code then set a false 440 code. If you need detailed information on how the system works let me know.
There also is a service bulletin addressing a problem with the close canister valve which is mounted to the air cleaner. This valve seat has a tendency to leak. This will set the two codes that you have plus it normally will pop a 441 code along with them.