Subaru Forester 2005 Small & Large Evap Leaks detected


I have a 2005 Subaru Forester with about 124,000 miles. I’ve had her since 2012. This year has been rough for her and every month or so there seems to be something that I need to fix.

This time, the check engine light is on, and the cruise light is flashing. Two codes came up:
P0442 - Small Evap Leak
P0457 - Large Evap Leak

I brought it to a local auto service shop, and they replaced the gas cap, and also cleaned the filler neck with several grits of emery cloth. They cleared the codes, and told me to drive it for a few days.

Well the check engine light came on again the other day.

I was planning on bringing my car in today to the shop to see what the codes were this time. I’m assuming probably the same thing.

They told me I may end up needing a smoke test, but I’ve been reading some online forums and some folks are saying that isn’t always necessary and could just be another way to get money out of car owners who do not know a whole lot about cars.

Also: My car inspection is due this month. The codes came on at the beginning of the month and I’ve been working on trying to get this fixed all month–I’ve brought it to 2 other places who were of no help. I’ve spent about $210 so far. I don’t have much money to be throwing away on this if it’s just a crap shoot of a car anyway. I have been considering just trading it in for a new car.

Does anyone have any thoughts or opinions on this? Your advice is much appreciated!

Actually you do need a smoke test. It will pinpoint the leak source. Otherwise mechanics will just be guessing and throwing parts at it randomly.

Don’t give up on it yet. It’s a low mileage car with plenty of life left. New car payments will be more expensive than keeping this one. Find a trusted local mechanic in the Mechanics Filed section of this website. Have him do a smoke test to locate the leak. It could be as simple as a cracked fitting or hose.

Thanks for the advice. I forgot to mention that one of the repair shops also said that it could be the sensor itself is bad and needs to be replaced.

Does anyone know if this would be smart to check out first, before doing the smoke test?

I’d do the smoke test first.

Yes, smoke test first. It’s not that expensive. Otherwise you are just guessing and wasting $$.

Thanks guys, I appreciate your advice!

Have an awesome day!!

If you are getting the CEL right after filling the gas tank, you are probably overfilling. You have to stop on the first click or the excess gas will get into the vapor lines and saturate the canister and clog the vent valves giving you the codes.

Most of the time, if you stop overfilling, the condition will clear up on its own in a few days or weeks. If it doesn’t clear up on its own, then things will get expensive, $4-600. Even if you do not typically overfill, the former owner may have and did it often enough to actually damage to vent system and canister.

I am not getting the CEL after filling up. I have had this car for 2 years and this is the first time this issue has come up. Also I never, ever continue filling my tank after the first click.

That’s good. I’m guessing you do, in fact, have an evap system leak. It can leak in strange places. I’ve seen leaks in the rubber hoses hidden above the gas tank where mice have chewed through the hoses. That’s why smoke testing is critical, because otherwise leaks in those hidden places cannot be found.

Those small shops aren’t doing you a service by selling you diagnostic steps one at a time.

The shop I work at charges a $90 diagnostic fee for a check engine light. Sound high but it is for a complete diagnoses (in most cases). If there is a evaporative emissions leak it is identified and an estimate given. The customer doesn’t choose the method of testing, IE; smoke or pressure.

BTW it has been more than twenty years since I accused a customer of damaging a evap. system by over filling a tank. Especially with second generation evap systems, if the tank was allowed to become over filled there is a problem with the fuel tank fill control valve.