P0440 code

[edrach]

'97 Impreza L wagon with 5MT transmission (189K on the car) dropped this code on me recently. It will clear, but comes back the next day. I've checked the gas cap and it looks okay; and it's tight. Not sure where we would go from here.

[allwheeldad]

I had been plagued by this code for a year. When the fuel filler neck dumped gas on the ground while refuelling, the cause became aparent. Take the salt trap, I mean plastic shroud, off of the fuel neck and have a look. The valve at the top of the neck rotted right out on my LGT. You might also try looking at the sensor coming into what I believe is the charcoal filter box (if Imprezas are anything like Legacys) that is behind the passenger side rear wheel. I had to solder on some new wires because mine had corroded and threw the same code.

[Fairtax4me]

Take the salt trap, I mean plastic shroud, off of the fuel neck and have a look.

X2 Make sure the filler neck isn't rusting out anywhere, and none of the rubber hoses in that area are cracked or split. Check the hoses at the vapor canister as well. That might be behind the right rear wheel under the car or it might be under the hood.

[Scoobywagon]

According to Alldata, its behind the rear passenger side wheel. There are some LARGE hoses in and out of that thing. Make sure they aren't kinked or torn.

[OB99W]

Check what's already been mentioned. If you don't find the cause that way, see:

http://www.endwrench.com/current/02SpringInsiderInfo.pdf

http://endwrench.com/pdf/fuel/MoreP0440TipsInfoW00.pdf

http://www.endwrench.com/pdf/fuel/FtEvapEmissionTestW00.pdf

[edrach]

I'm really puzzled here. I checked under the rear passenger side wheel looking for hoses, cannister and whatever else should be there. There are no rubber hoses at all. Everything is metal; the main filler tube and the smaller return line are all one metal piece. Also, no canister, solenoid, etc. that I can see. I'll confirm I have a '97 Impreza L wagon.

 

According to the endlink article, the canister should be located in the rear luggage compartment. I don't see it there either.

 

Lastly, I can't turn off the CEL light for this code. I can clear the code but the CEL won't go off until the third or fourth time the code re-appears and is cleared. Then, after a day or two, the CEL light comes on again and we start the same sequence over again.

[snowscooby]

I don't know if you have already seen this or not, but it gives some basic steps to follow for your problem. I hope it helps!

 

http://www.obd-codes.com/p0440

 

To my knowledge I have the full FSM for a 97 Impreza L in PDF form. I found several pages on the EVAP system including a full assembly page on the fuel tank/ system. I am going to see if I can locate the reference page the diagnostics section is referring to and see what that says about p0440.

Edited August 18, 2010 by snowscooby

[snowscooby]

I am pretty sure I found the area in FSM that has what you need. It says to remove rear right wheel, Remove bolts (3 bolts) which install protector cover on body, while releasing the underside of the protector unhook it. It shows the evap hoses underneath that protector plate.

 

Also I have a diagram for the fuel delivery system, return, and EVAP.

[edrach]

I don't know if you have already seen this or not, but it gives some basic steps to follow for your problem. I hope it helps!

 

http://www.obd-codes.com/p0440

 

To my knowledge I have the full FSM for a 97 Impreza L in PDF form. I found several pages on the EVAP system including a full assembly page on the fuel tank/ system. I am going to see if I can locate the reference page the diagnostics section is referring to and see what that says about p0440.

I bought and installed a brand new Subaru gas cap today. Also by co-incidence filled the tank on my way home. Thanks for the all-data info. My problem is I have no clue where to find the canister or purge solenoid.

 

I also have the complete FSM for a '97 Impreza also. With the info there, I still haven't found the canister or solenoid. Neither of them are in the rear passenger well and there are no rubber hoses on the filler assembly. I don't have a select monitor, so I can't follow the diagnostics until I locate the parts.

 

Hopefully the new gas cap did the trick. I'll see tomorrow if the CEL comes on again.

[edrach]

I am pretty sure I found the area in FSM that has what you need. It says to remove rear right wheel, Remove bolts (3 bolts) which install protector cover on body, while releasing the underside of the protector unhook it. It shows the evap hoses underneath that protector plate.

 

Also I have a diagram for the fuel delivery system, return, and EVAP.

What page is that info on? I haven't found that specific info yet.

[ShawnW]

The canister is either on the right rear of the car near the bumper and is a black box about the size of a childs shoe box maybe 8x3x6 or so....

 

or

 

The canister is under the hood and is round on the passenger side behind the headlight.

 

The purge valve is on the intake manifold and under the risers.

 

I would say the cap is about a 50/50 on this code, the other half are almost always corroded fuel filler neck or bad hoses near there.

[snowscooby]

I found the information on 2-8 [w3a0] pg. 16 under the service procedure for fuel filler pipe. Also in 2-8, [W7A0], there is the service procedure for the fuel delivery, return, and evap systems.

 

On my 1997 impreza sedan there is a mysterious black canister behind the passenger side headlight that has a couple hoses going to it. I think I can smell gas vapors when I undo those hoses so that might be what you are looking for.

 

If you can't find the pages I listed, I would be happy to email them to you as they are all in easily accessible pdfs on my computer.

[johnceggleston]

on my 97 obw the canister is under the hood, on the 98 obw (10/97 build date) i just got, it's not there.

 

if under the hood it's about the size of a quaker oats container, 5-6" diameter, ~8" tall and black hoses run from it to the front corner of the engine just under the power steering lines near the passenger side fuel rail? .

 

hope this helps.

[edrach]

Well, so far so good. A whole day and a half without the CEL lighting up since I replaced the gas cap. I'll wait to see if the code stays gone for a week before I'll declare it fixed. Thanks to everyone who replied.

[neilinda]

'97 Impreza L wagon with 5MT transmission (189K on the car) dropped this code on me recently. It will clear, but comes back the next day. I've checked the gas cap and it looks okay; and it's tight. Not sure where we would go from here.

 

i have a '97 Legecy wagon (5speed, awd, 210k), and i'm having a similiar problem.

The check engine light is usually on. My local tire shop will read (and clear) the code for me -PO440- which should be a large evap leak with the only symptom being that you should smell gas around the car. Well, no gas smell, no change in gas consumption, and if i keep the tank at 3/4 full or more, the light will stay off. If it's on, it will even turn itself off after a week or so of not letting the tank drop below 3/4 tank. Earlier in the summer, we did have a pinhole leak in the fuel tank filler tube (that had been hidden under the shield), but we have replaced that (although the new one did not have the little plasic flap in it that the old one did).

We have also replaced the gas cap... and keep it tightly closed.

Anyone have any ideas?

 

---neilinda

[snowscooby]

Did you get the p0440 code immediately after you fixed the pin hole leak? I would re-inspect the evap system (all of the hoses and the canisters) and possibly look into the fuel tank pressure sensor? If the sensor was reading incorrectly it may only register with a certain amount pressure, therefore a tank with 3/4+ would trigger it to read correctly? Thats just a theory, I am not sure how the ECU interprets fuel pressure information in relation to the EVAP system.

[edrach]

Well, so far so good. A whole day and a half without the CEL lighting up since I replaced the gas cap. I'll wait to see if the code stays gone for a week before I'll declare it fixed. Thanks to everyone who replied.

Well, I spoke too soon; after a few days and a trip to WCSS12 and back the code returned shortly after I gassed up.

 

When I got home I checked the engince compartment for the charcoal cannister and it's not there. Without taking any paneling or covers off the rear I haven't found it in the rear luggage area or passenger side wheel well of my wagon.:-\

[Scoobywagon]

It won't be inside. You'll have to get on your back under the rear passenger side corner. There's a brace there that unscrews easily and the whole thing will drop out.

[snowscooby]

Have you checked in the engine compartment behind the passenger side headlight? I am pretty sure that is where mine is (97 impreza sedan). Did you check the hoses behind the rear passenger tire (behind that metal plate)?

[neilinda]

Did you get the p0440 code immediately after you fixed the pin hole leak? I would re-inspect the evap system (all of the hoses and the canisters) and possibly look into the fuel tank pressure sensor? If the sensor was reading incorrectly it may only register with a certain amount pressure, therefore a tank with 3/4+ would trigger it to read correctly? Thats just a theory, I am not sure how the ECU interprets fuel pressure information in relation to the EVAP system.

 

 

No, as odd as this sounds, we've been getting the PO 440 code on and off for around a year. Ever since i decided to try to let the gas run very low to see if there is a warning light that would let you know when you get down to the last gallon. Up until then, we had no trouble. What happened was, i would let the tank run low... no -low fuel- warning light would come on, and then i would get nervous about running out, and get gas. i finally put a small can of gas in the car, so i wouldn't worry about it, and instead of a low fuel warning light coming on, the cel came on instead -at least that's how it seems. Ever since then it as spent pretty much time on. The local mechanic i use read the code, checked what he knew to look for and advised me to make sure i keep the gas cap tight. He's looked under there a few times, and has never noticed a problem. We discovered the pin hole leak, because one time i went to the store (which is very close to the gas station) right after filling it, and gas was leaking on the parking lot.

 

i will have my husband and brother (a GM mechanic) check the evap system -hoses, etc - and actually also read them your post.

 

My brother has been thinking it might be the pressure sensor, but he is unfamiliar with the Subaru system (and -whenever i have a problem with my car- is always making snarky comments about Subarus).

Do you know where the pressure sensor is?

 

---neilinda (linda)

[edrach]

I visited richierich's shop in Portland yesterday and he put it on the lift and I now know where the cannister and purge solenoid are (not in the rear wheel well, but behind the wheel). He did find any bad hose or faulty wiring. However, everything is covered with a thin coating of mud from the rallycross activity. I'll pressure was off the mud and viisit pull a part and yank a "younger" cannister and purge solenoid (I'm pushing 192K on my Impreza) and install them on my car. No point in spending about $300 in new parts trying to "guess" which part is bad.

[snowscooby]

My brother has been thinking it might be the pressure sensor, but he is unfamiliar with the Subaru system (and -whenever i have a problem with my car- is always making snarky comments about Subarus).

Do you know where the pressure sensor is?

 

---neilinda (linda)

 

What car do you drive again? I can check my FSM's for the pressure sensor when I get back home from my trip.

[edrach]

What car do you drive again? I can check my FSM's for the pressure sensor when I get back home from my trip.

'97 Model L Impreza wagon; EJ22 engine with 5MT transmission.

[Fairtax4me]

I visited richierich's shop in Portland yesterday and he put it on the lift and I now know where the cannister and purge solenoid are (not in the rear wheel well, but behind the wheel). He did find any bad hose or faulty wiring. However, everything is covered with a thin coating of mud from the rallycross activity. I'll pressure was off the mud and viisit pull a part and yank a "younger" cannister and purge solenoid (I'm pushing 192K on my Impreza) and install them on my car. No point in spending about $300 in new parts trying to "guess" which part is bad.

 

Did he hook the smoke machine up to it to look for leaks?