Check Engine Light

I hav a 2004 Toyota Corolla- the CEL has been on for months- the code is for small evap leak
I have tried cleaning rust from filler neck at gas cap- no change
I have had a smoke test done with no leak found
Any thoughts or common problems?

The charcoal canister?

Remove the gas cap and apply a small amount of petroleum jelly to the seal on the gas cap and reinstall the gas cap. If this causes the CEL to turn off, replace the gas cap.


Try what tester said but I can almost 100% guarantee it’s the Charcol canister as RemcoW said. I had a scion xA from that time period, basically the same car, and this issue came up if a certain recall wasn’t received and heeded that allowed water to seep down the filler and into the Charcol canister.

On the plus side, if you really do some googling around about Toyota Charcol canisters, there are some guys who came up with some interesting solutions to this problem including cleaning a valve on the Charcol canister ad taking the canister itself, and I know this sounds crazy, and baking it. Look around.

Also, can you post the code or codes pulled? If you have two or three, it’s some certain combination of codes, it’s pretty much a lock that it’s the canister.

Actually, just a quick note here since I don’t know you.

Find out what someone did with their canister exactly before you go throwing it in the oven. If you have an electric oven and crack the door and find a way to circulate the air out, I think you’d be ok, but if you have a gas oven and throw a gasoline saturated canister in there, well that sounds like a good recipe for a bomb.

Spend 10 bucks and replace the vacuum hoses.