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EVAP Very small leak detected (Code P0456)

I have the check engine light ON. I checked the code it is Code P0456 (EVAP Very small leak detected).

Replacing the gas cap used to fix the problem, not anymore.

Please give me suggestions. On the manual, I found dozens of possible reasons, but no hint about how to troubleshoot.

The vehicle is a 2003 Toyota Tundra, V8

Thak you

J. M. Banderas

Do you require an emissions test? After CEL reset, how long will the light stay off?

You can spend a lot of time and money chasing these “problems” and accomplish little or nothing…

A “very small leak” that isn’t from the gas cap can be very difficult to find - as Caddyman says a lot of time & money could go nowhere.

The most straightforward thing is to get a smoke test done to find the leak. This will likely run about $100. It would probably find it but might not.

Another thing to do requires more time than money & that would just be to run new evap lines. The hard part is getting at the connections at the gas tank. The stuff under the hood is probably not all that hard.

After resetting, the light stays OFF for about 30 miles.

Hmmmmm. Replacing the gas cap used to fix the problem, not anymore.

Perhaps the new cap seal won’t seal tightly onto a rusted fuel filler pipe.

Rust build up around the top of the pipe will cause a non-tight connection.

You could try and sand off or file off some or all of the rust.
(Place a clean rag tightly in the pipe to prevent rust from getting into the tank)

Do NOT use a power grinder.