Possible for evap leak to fix itself?

[My Nameis]

So for a long time about over a year my 98 civic ex kept throwing an evap leak code.

Had it smoke tested and couldn’t find anything. Since the car doesn’t need emissions testing anymore I just kept driving it and clearing the code with my obd2 wifi scanner.

About two months ago I decided to replace my fuel filter and since then the code stopped coming on. Doesn’t make sense because the fuel filter isn’t part of the evap system.

Another thing, when the code first started I had always gone to a full service gas station where they’d top off to the amount you requested even if tank was full.

I started pumping my own gas since without topping off after the pump shut off.

Now I’m wondering, if say the previous practice caused the evap canister to saturate with gas causing issues, could it over time have dried and now system works as it should or?

Topic

[college man]

Maybe it was overfilling that caused it or the gas cap was loose. Usually
these things don’t fix themselves.

[Scott Osborne]

It could be due to your filling habits. I know that many cars only test the evap system when the tank is below 80% full and above 25% full. If you reset the code and never meet the requirements for the test you wont get a CEL but when you pull codes you’ll get a evap not ready.

The other thing is the gas cap is part of the system. If its not installed correctly you will get the small evap leak code.

The other thing (Especially on Toyota Trucks) is you get solenoid valves that leak internally and give you intermittent small leak codes.

Collegeman is right. Evap leaks don’t just go away. But I’ve seen them hide for a time and come back…Sometimes as a large leak code

[My Nameis]

Yes in fact mine came back. Very strange. I do wonder if it’s a leaky solenoid that’s not making it easy to catch

[David]

Just dealt with an evap code (large leak) on our 05 Odyssey – definitely frustrating to chase down! – ended up being either the vent float assembly (it’s separate from the tank on the Odyssey) or the pressure sensor o-ring on the charcoal canister (those were the last parts I replaced, and the code went away – the float wasn’t working properly, so it was probably that (letting liquid fuel get where it’s not supposed to be) but the o-ring was pretty dried out, too, so who knows.

I went through the whole system, disconnecting and inspecting every seal/tube junction. I also replaced the vent shut valve as it wasn’t opening/closing properly.

[Author]

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