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Evaporitive cannister

I had to replace the evap. cannister on my 2004 Toyota Camry. My mechanic told me it was due to overfilling the gas tank, i.e. topping it off. Is this true?

No. Since 2000 all vehicles are equipped with a ROOF (Roll Over/Over Fueling) check valve at the fill tube. This prevents over filling of the gas tank causing damage to the EVAP system.


I had not heard of ROOF, so thank you.

What problems were you having that made you replace the canister??

“check engine” light came on. Had it diagnosed at Toyota dealer for $75.00.

I hate to ask what the repair cost was… These canisters usually last the life of the car…They are an emissions control device. If you are not subjected to emissions testing, replacing them can be deferred indefinitely…

unfortunately it will not pass New York State inspection if not replaced. Toyota dealer wanted $500+ for replacement. I bought it from Sparks Toyota for less half of the price.

Thanks for that information Tester. I did not know they had changed over at a given year, nor did I know that the function (or a function) of the check valve was to prevent over filling the and damage to the EVAP system. Of course my wife has a pre EVAP car and I have a diesel. I believe neither applies (I guess they might have the check valve in my diesel, but I don’t think it has one.