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· Registered
2007 Forester
4 Posts
Discussion Starter · #1 ·
I have had my forester for about 3.5 years and I have always had issues with this code popping up every time I go on a long distance trip. The code says "Evaporative Emission System Leak Detected (very small leak)". The most common fix for this issue is supposed to be change or tighten the gas cap. I have tried out several different gas caps and it wont fix this issue. If I clear the code, it will pop back up after driving on the highway for about 50 miles.

Anyone know what this could be?

· Registered
2012 Forester X Auto
3,636 Posts
@iankelley151 There is a lot more to the emissions system than the gas cap.
The cap is just the most common issue, and generally that is when the cap is damaged or the wrong cap.
But, since the code is issued
on a long trip sounds like it may just happen when there is more heat than usual... That will make it harder to find, because under "normal" circumstances, there isn't anything wrong.

You most likely have a hose or connection leak somewhere that has enough integrity to maintain pressure in normal circumstances, but loses pressure when subjected to more than normal, if indeed you have a good fitting cap...
You could examine all the hoses and connections between the fuel tank and the emission canister and examine the tank itself, and maybe you'll get lucky. Intermittent problems are hard to find, but you could pressurize your fuel tank and simulate the high pressure condition (put a hose tap on one of your gas caps and add a few pounds of pressure with a pump) and you might be able to hear the leak hiss. .

I would just clear the code and live with it, unless it happens more frequently.
You should also get a code reader that allows you to clear codes if you don't have one, so that you don't ignore a major CEL problem because the minor issue is hiding it.
That will also allow you to clear the code while on a trip, and see if the code comes back immediately or doesn't.

This information will be relevant to how the leak is leaking...

· Registered
2010 Forester 2.5 XPremium 4EAT
928 Posts

Go to a good search engine and search for " Forester P0456"

You will find at least 6 threads listed from this forum, which may help you.

Unfortunately, the 'Search Community' function at the top of the page is next to useless in returning results.
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