P0440 Code

[jamesm113]

A code P0440 could mean one or more of the following has happened:

 

The gas cap is not installed or working properly

The purge solenoid has failed

The canister is plugged and not working properly

 

I made sure the gas cap is on tight, but the code came on again.

 

Where is the purge solenoid and canister located? Any other things that could cause this code?

 

Thanks

 

EDIT: 97 Legacy L wagon w/ 132k

[johnegg]

95 - 97 the canister is up front under the hood passenger side near the head light, sort of. starting in 98 they moved it to the rear of the car between the fuel filler and the tail light underneath.

[jamesm113]

Thanks, and is 42084PA050 (Valve, 2 way), which right by the canister, the purge solenoid?

[jamesm113]

I should also add I smelt gas in the rear of the car a few weeks ago, before the light came on...

[Baddog]

So this purge canister. Is it that little cylinder thing near the ABS?

 

If so...I don't have one and I have a 96.

[johnegg]

I should also add I smelt gas in the rear of the car a few weeks ago, before the light came on...

 

if your gas filler tube has a leak i think that can throw a code.

 

if you remove the rear right wheel, you will see the gas filler tube. there is a plastic protective cover on it that can hold dirt and water causing it to rust out.

[Osei]

^+1

Generally the p0440 code is caused by a loose gas cap.

In light of the gas cap being tight and that you smell gas,as Johnegg states you probably have a hole in the filler neck.

Just FYI, on some of the 97's (2.2l AWD)the canister is behind the right rear wheel close to the end of the car. There are three hoses, if one has come loose or developed a hole it can also cause you to get that code. Check. It's a rectangular box.

 

The purge control solenoid can either be mounted on the strut tower or on the passenger side of the intake manifold below the throttle body.

 

The cylinder thing with the sensor and two metal lines coming from it is the AC dryer.

 

For future ref. http://www.main.experiencetherave.com/subaru_manual_scans/

O.

Canister.pdf

Purge Control Solenoid Valve.pdf

[jamesm113]

Gas filler tube looks good, a little dirty, but no rust... I guess that's the beauty of having a car that spent the last 11 years in California - no rust

 

Yea, I was just looking under the hood and couldn't find anything resembling a canister.. I will take a look in the back.

 

Thanks, i'll let everyone know what i find.

[jamesm113]

Okay took a look in the back, canister looked OK to me, no gas spilled out of it and nothing slushed around inside it... is there anyway to check it?

 

Hoses looked good. Air filter held vacuum. The bottom of the gas tank had a little scratch on it, but it looked superficial. Nothing was leaking out of it and everything was dry. I JB welded it anyway.

[vicdeng]

check your filler neck. Most of them nowaday are rust real bad. I just changed it on my wife's 99 outback, and it fixed the code.

 

if you smell gas, i am pretty sure your filler neck is rusted.

[Osei]

Google p0440 code, you'll find things to do.

With car running and using a spray bottle with soap in it, spray around the vacuum lines to check for any leaks.

Check continuity on purge control solenoid valve , yours may be on the strut tower or under the throttle body.

Unity should have 12V when key in on, but not running position.

Resistance of unit should be 40 ohms.

If all this checks out, try a simple purchase. Replace the gas cap. After 14 years it may not be sealing like it should.

After this I don't have any real help.

I am chasing a bad purge valve myself (p0443) at this time.

 

O.

[jamesm113]

check your filler neck. Most of them nowaday are rust real bad. I just changed it on my wife's 99 outback, and it fixed the code.

 

if you smell gas, i am pretty sure your filler neck is rusted.

Believe it or not, my filler neck is in good shape. No rust, just a little dirt.

 

Google p0440 code, you'll find things to do.

With car running and using a spray bottle with soap in it, spray around the vacuum lines to check for any leaks.

Check continuity on purge control solenoid valve , yours may be on the strut tower or under the throttle body.

Unity should have 12V when key in on, but not running position.

Resistance of unit should be 40 ohms.

If all this checks out, try a simple purchase. Replace the gas cap. After 14 years it may not be sealing like it should.

After this I don't have any real help.

I am chasing a bad purge valve myself (p0443) at this time.

I'm pretty sure I saw this on the front passenger strut tower, I'll have a look. My friend has a nice DC power supply, I'll use that test the solenoid.

 

What is the solenoid that's above the vacuum canister in the rear passenger side of the car? Is that the vent solenoid? How come it was connected to an air filter?

 

Thanks

[Osei]

My error. Unit on tower is pressure control solenoid.

The purge valve is on manifold under throttle nody.

unit near canister is vent control solenoid valve.

Use link I gave in earlier post and load the 97 FSM.

All I am giving is in there.

 

O.

[jamesm113]

Thanks, I had a look at those earlier but they only have info about the canister and a picture of the purge control solenoid (nothing about it's location).

 

Also I switched gas caps with my friend's Tacoma yesterday.

 

During my lunch break today, I unscrewed the gas cap on my car and I heard a whooshing sound as air rushed in/out (didn't pay attention to the direction, oops). This means the EVAP system is holding pressure/vacuum, correct?

 

I called my friend (whose truck has my gas cap) and had him unscrew the gas cap on his truck. He heard air being sucked in.

[Osei]

Read on another thread about the vent solenoid wires being corroded.

If you heard whooshing the vent solenoid is not operating properly.

Right in front of the canister is the vent solenoid. Peel the wires back a little to make sure that the contacts are not broken or corroded.

http://www.ultimatesubaru.org/forum/showthread.php?t=121515&highlight=vent+control+solenoid

Hope this helps.

 

O.

[jamesm113]

Well, I hadn't turned on the car since I switched gas caps. It sat from probably about 5pm (around 70F) to noon the next day (80+F) when I loosened the gas cap and heard the whoosh. My friends truck sat for the same time period as well. Neither car was turned on or running.

 

I just finished checking the vent solenoid (above the canister) and purge solenoid (on the passenger side of the intake manifold).

 

The purge solenoid was closed until 12V was applied, then it opened, and vent solenoid was open until 12V was applied, then it closed, so it appears both solenoids are working correctly. I measured 25 ohms on one solenoid and just under 28 ohms on the other (I forget which one was which).

 

I plugged the air vent above the vent solenoid and used a vacuum pump to the line connecting to the drain side of the charcoal canister (the one without a hose clamp). Everything held vacuum OK. So the air filter is fine.

 

I then tried the small hose on the charcoal canister, that held vacuum as well.

 

The big hose (with the clamp) didn't hold vacuum, but i'm assuming it's because i had the purge solenoid lines disconnected in the front. I will try this later. EDIT I tried this today (8/18/11) and it does hold vacuum

 

Thanks

[jamesm113]

Well, about 2 weeks later, the P0440 code came back.

 

To recap:

*Switched gas caps with a friend. Both mine and his hold pressure (we let our cars sit on a hot day, and opened the gas cap and heard hissing). I got the code with both gas caps. I always let the gas cap click 3 times when tightening.

*Both solenoids good.

*No rust on filler neck.

*All 3 hoses going into canister hold vacuum (I plugged the vent line)

 

So I think there could either be an issue with the solenoid signal wires OR the evap canister. Is there a test to check these?

 

Thanks

[Osei]

PM me your e mail and I will send a list of all DTC's and diagnostics for them.

 

Just picked up a 98 Impreza Outback and I am chasing the same code.

Since it is not on the road yet I am going to remove the evap canister and leave it in the sun for a day. I am sure the charcoal is kind of saturated after 13 years of running. Will check the others after I reinstall.

 

O.

[jamesm113]

Just ran the diagnostic mode (green connectors under the dash in case any future googlers want to know where to look) on my car from the pdf you sent me. it was a little hard to hear because it had everything cycling on and off, including the fans, but I confirmed the purge and vent solenoids were working correctly. However, I wasn't sure if the pressure control solenoid was working correctly or not, so when I pulled the hose to to bench test it I broke one the plastic connectors off another component (labeled M130 7B17). However, it looks like it might have already been leaking so I maybe I lucked out. Now just to figure out what this piece is... EDIT It's the rollover valve, $35 from the dealer, part 42084KC060

 

I also inspected the fuel lines from under the seat all the way to the firewall. Everything looked good and nothing smelled of gas

[jamesm113]

Hmm, my pressure control solenoid valve may not be working correctly- it is always open, even when it's connected to 12V (I've both bench tested this and tried it using diagnostic mode)

 

Osei, do you know how this valve is supposed to work?

 

I found this link, which is about Geo's but says the pressure control solenoid valve closes under the following conditions:

*Engine off

*Engine is running, vehicle stopped and fuel level is higher than specified valve.

 

Could that be true for our Subaru's as well?

 

Thanks

[Osei]

From what I see, it should be closed normally. The pressure sensor(mounted on the strur tower) senses atmospheric pressure, When the solenoid valve senses a higher pressure than designated, it opens and allows the vaccum from the intake manifold to pull in fuel vapors from evap canister.

See P1143 and 1144 in the diagnostic chart I think I sent you. If not, advise and I will send it.

When the green test connectors are plugged in the solenoid should click. I know its hard to discern, since everyting else is clickin. Then again, it may click but not operating.

Not much help here, but that's what I got.

 

O.

[jamesm113]

From what I see, it should be closed normally. The pressure sensor(mounted on the strur tower) senses atmospheric pressure, When the solenoid valve senses a higher pressure than designated, it opens and allows the vaccum from the intake manifold to pull in fuel vapors from evap canister.

See P1143 and 1144 in the diagnostic chart I think I sent you. If not, advise and I will send it.

When the green test connectors are plugged in the solenoid should click. I know its hard to discern, since everyting else is clickin. Then again, it may click but not operating.

Not much help here, but that's what I got.

 

O.

I think we are talking about different pressure control solenoids. I uploaded a picture of the one I am referring to. It is located in the back of the car, between the fuel tank and canister. Step 10AR5 in diagnostic chart you sent me. It clicks when energized/de-energized, but it's a very faint click which leads to me to believe it could be broken (+ the fact it stays open all the time).

 

But it looks like I have another set of hoses and solenoids I need to test

[Osei]

Sounds faulty, but check over on USMB for other opinions.

 

O.

[jamesm113]

Were you ever able to solve your P0440 code Osei?

 

Mine is still persisting. Just finished using a homemade smoke machine yesterday and couldn't find any leaks, but was able to confirm the purge and vent lines are not clogged.

[jamesm113]

I found the leak. Air ventalitor hose going from the gas tank to the fitting in the wheel well. PO replaced the hose with a gates 5/8" marine hose which had both the wrong ID (too small) and OD (too big). The hose clamps were on too tight and caused both ends to crack

 

Replaced, gas smell eliminated.

 

Was able to plug the air vent hose with my thumb and have a friend pull a vacuum from the purge control solenoid hose over the hole system with no drop in pressure.