subaru P440 code

Hi Gang.

Wifes car (98 forester S with 185,000) keeps poping a P440 code = "Evaporative Emissions Control System Malfunction"

At first i thought okay the gas cap is loose. reset it was good a few weeks.
Popped it again i checked the charcoal canister lines they look fine. Two day later again. Okay... Uncover tank fill pipe it's rusty but not real bad i don't see any holes. but i wire brush it and coat with fiberglass resin and then wrap it with soaked glass just incase. Next day popped again. Replace the gas cap with Factory unit. Just got e-mail it popped on her way to work...

The web turns up little.

Any clues?

Thanks 44dwarf

PO440 is a pretty generic leak code. It can be a hose leak, sounds to me like you have checked all the quick stuff, it might be in the purge valve. If those don't seal you'll get a 440 code. Sometimes it can be a failure of the leak detection pump itself, if the PCM doesn't see the pressure rise/drop when it requests a test then it may think there's a general evap failure when the problem is really the pump not firing up. Best way to tell is to bite the bullet and let the Scooby dealer do a 'smoke test'.

A quick Google 'PO440 Subaru' shows a lot of salt area cars having rotted fuel filler tubes causing this. You may have been on the right track there.

Not that its a Subaru, but we had a Buick in the shop on Monday with the same code. Put the smoker on it and it poured right out of the filler neck. Granted, this one looked (and was) made of nothing but rust scale, but even one tiny, imperceptible hole could cause such a code.

Fill pipe is a dealer only part $118.57.

We get pleanty of salt here and now with the Alky in the fuel i'm sure its not helping.

I did find a www.endwrench.com write up on testing the system with factory tools.

She's taking the car for a four day girls weekend so will look deeper next week.

44

If it is the fill pipe, remove it, clean it and use the gas tank mend epoxy kit and reseal it.

Joey 48442 had a terrible gas leak last week and did this with great results.

I'd wager a rusted fuel inlet too. I did some quick searching to see if there was any kind of quiet recall on those but didn't find anything. Here's another link that may be helpful if it ain't that: Scoobymods