P0446 code on 05 Camry LE

[sonny in mn]

My wife bought this car new in 08/05. We have had 2 charcoal cannisters replaced under warrantee. Check engine light comes on & code reader says P0446, may go off in 50 to 100 miles. Not a loose gas cap or seal. Dealer says we probably need another cannister & the problem is our 2.5 miles of gravel road. At this rate we will need a new cannister every year. This is a great car except for this problem. I have 2 GM vehicles 190K & 120K with no such problems. I've searched this forum some & read about the VSV valve, but that it may be integral to my cannister. Has anyone had similar issues? Any help or comments are much appreciated. Sonny

[TRD VVTi]

The canister is probably getting damaged by rocks from your dirt road.

I'd check to make sure that it's leaking. If it is, I'd replace it and insulate it so that it doesn't continue to get damaged and leak.

EDIT: Just and extra note. Over-filling your car will fuel can cause premature canister failure also.

[toyomoho]

Never seen this problem because of rock damage.

If the problem is the canister, asks the dealer to show you the old part(s), ask why and how it failed. See for yourself if it was rock damage.

If it was rocks (don’t assume anything until proven to you) then as TRD states adding some kind of shield will prevent the problem from reoccurring. This can be a very simple shield made of sheet metal or plastic. Ditto on not overfilling the tank, just let the pump shut off and stop pumping.

If rock damage Toyota should have designed things with a little more protection as in some areas gravel roads are very common.

[Nad1370]

Wonder if they (the dealer) are running the evap test first before they give it back to you to make sure it is running correctly.
It'll usually throw a pending code if there is something wrong.

I'd get more info on actually what they found out to think it's a canister problem. Twice!!

[sonny in mn]

My wife will typically fill the tank, (she stops on ist clickoff) on her way to work. She parks less a 1/4 mile from where she gets gas. I wonder if that creates excess load on the cannister? I just spoke to a friend with the same car, also on a dirt road. He has 70K on car & has never had any fault codes.

[ShawnM]

A scanner and a smoke test would easily pinpoint the leak. They should be running the test again after replacing the canister to double check it for other small leaks. Filling up the gas and driving a short distance does not effect the canister in any way.