P0440 Code

[Ravi]

I have a 1999 Subaru Outback Legacy. I started to see the CEL light
come on about 4 weeks back. I took it to autozone and they scanned it
as P0440. I made sure my gas cap was tight and reset the error. After
about an hour of driving, the light came back again.

This time I replaced the gas cap and reset the error. Just like last
time, the error came back (and I confirmed that it was the same code)
again.

The guy at Autozone said I could have a leak in my hoses and
recommended I buy the Carb cleaner and spray each of the fuel carrying
hoses to see if I can identify a broken hose. He said if there is a
leak, I would hear the engine rev up.

Let me know if you think this is the way to diagnoze the problem
further. I searched some stuff online and the Purge valve came up as a
possible cause.

All suggestions are welcome.

Thanks in advance
Ravi

 

[1 Lucky Texan]

I have a 1999 Subaru Outback Legacy. I started to see the CEL light
come on about 4 weeks back. I took it to autozone and they scanned it
as P0440. I made sure my gas cap was tight and reset the error. After
about an hour of driving, the light came back again.

This time I replaced the gas cap and reset the error. Just like last
time, the error came back (and I confirmed that it was the same code)
again.

The guy at Autozone said I could have a leak in my hoses and
recommended I buy the Carb cleaner and spray each of the fuel carrying
hoses to see if I can identify a broken hose. He said if there is a
leak, I would hear the engine rev up.

Let me know if you think this is the way to diagnoze the problem
further. I searched some stuff online and the Purge valve came up as a
possible cause.

All suggestions are welcome.

Thanks in advance
Ravi

Well, that technique would only work on a vacuum hose I think.
Has there been any damage or work done on the vehicle prior to this?
The system involved, in addition to typical hoses, has plastic
components that could be cracked.

let us know what you find

Carl

 

[S]

Hi Ravi !

I have a 1999 Subaru Outback Legacy. I started to see the CEL light
come on about 4 weeks back. I took it to autozone and they scanned it
as P0440. I made sure my gas cap was tight and reset the error. After
about an hour of driving, the light came back again.

This time I replaced the gas cap and reset the error. Just like last
time, the error came back (and I confirmed that it was the same code)
again.

The guy at Autozone said I could have a leak in my hoses and
recommended I buy the Carb cleaner and spray each of the fuel carrying
hoses to see if I can identify a broken hose. He said if there is a
leak, I would hear the engine rev up.

Let me know if you think this is the way to diagnoze the problem
further. I searched some stuff online and the Purge valve came up as a
possible cause.

All suggestions are welcome.

Thanks in advance
Ravi

You might be able to check vacuum lines with carb cleaner, but the
fuel lines are pressurized. You'll see (and smell) a leak in one of
the fuel lines. A better plan for the vacuum lines is to inspect the
hose where it slides up on to the nipple. If there are splits or
weather checking, or if the rubber is hard, replace the hose. There
are rubber hoses associated with the vacuum purge in front of the fuel
tank, behind the interior panel covering the right side rear wheel, as
well as on the purge canister and under the hood.
The purge valve is a 24ct bitch to get to, but a possible culprit.
About your only option is to replace it.
Another thing to look at is the filler neck; this will sometimes rust
thru in spots. It lives behind a cover in the passenger side rear
wheel well. Nicely hidden, but this area tends to collect mud and road
goo, with all too predictable results. Even if there isn't a rust
problem here (yet), take the opportunity to clean things up while
you're in there.

ByeBye! S.

Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101

 

[DK]

I have a 1999 Subaru Outback Legacy. I started to see the CEL light
come on about 4 weeks back. I took it to autozone and they scanned it
as P0440. I made sure my gas cap was tight and reset the error. After
about an hour of driving, the light came back again.

This time I replaced the gas cap and reset the error. Just like last
time, the error came back (and I confirmed that it was the same code)
again.

I had this on Forester 2002. Front oxygen sensor was faulty. After
replacement, the CEL went away and never came back.

DK