# HeLp: P0440 code and passing smog



## GOGOVDUBER (May 22, 2001)

okay i have erased this code and it comes back every week or so and now i have to take a smog test. question is if i erase the code before i take the test will i pass smog or do i really need to fix this before i take the test. not really sure what i need to fix but i guess i can start with the evap valve? thnx in adv!


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (GOGOVDUBER)*

No, your car will fail smog. I can't remember the last time I had my car smogged but in CA they defninitely do the tail pipe probe and probably read the codes. When you clear your codes or pull the -ve battery terminal you also clear the "readiness code". The guys at the garage check to see if the readiness code is set and if it is cleared you will automatically fail smog. After you clear your codes and start your car (and drive/shut off / drive) a few times all the emissions components will eventually be checked to verify all is working. After that cycle the readiness code will be set and the CEL will come on if it determined a component was failing. In your case the readiness code gets set and your CEL is coming on because of your code.
16824	P0440	EVAP Emission Contr.Sys. Malfunction
This should be an easy fix. It's the component that stores all the gas tank fumes in a carbon canister and after the car is started a solenoid controlled purge regulator cuts in and lets the gas fumes get sucked/burned in the intake. on the top-back side of the throttle body there is a black hose around 1/4" diameter. Follow that guy over toward the passengers side of the engine bay and it should hook into a donut shapped piece just behind the air filter box (this is the solenoid-purge regulator valve). Chances are this valve is stuck open or not coming on. When the car is warmed up and running if you touch this valve with your fingers you should feel it buzzing. If it is then it's working properly. If this valve gets unplugged for some reason or is faulty then you will get the P0440 code. With the sensor unplugged you can measure the resistance between its contacts. The valve should have some finite resistance and not open circuit. If it is open circuited or not buzzing then replace this valve. It shouldn't cost too much... under $20?
Good luck,
John


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## GOGOVDUBER (May 22, 2001)

*Re: HeLp: P0440 code and passing smog (bearing01)*

thanks for the info! how long after i clear the code and reattach the battery do i have to wait for this readiness code to be ready? i was going to smog it today but i guess i'll wait till this weekend so i can change the purge evap valve, some vacum hoses, and get another gas cap to be on the safe side.


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (GOGOVDUBER)*

Depends... but it probably will can be set within 15 minutes or so after starting up. I think if you cleared the codes, started up the car and drove for 5min, shut off the car and then repeated it 2 - 3 times it will definitely be set.
Some OBDII scanners show if the readiness code is set or not. Not sure if VAG-COM will indicate it. I never paid attention to this before.


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## GOGOVDUBER (May 22, 2001)

*Re: HeLp: P0440 code and passing smog (bearing01)*

ok i guess just to be safe i'll wait till sat to take the smog. oh by the way the purge regulator valve is pretty pricey at $100 so i'm just going to change the gas cap and some vacum lines. thnx hope i pass


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (GOGOVDUBER)*

Is the valve working? Is it buzzing to the touch. Change everything you want... if the valve is your problem then that's what you have to fix. 

As for replacing the gas cap.... unless you have a code that pertains to a pressure leak like P0442 then you're doing guess work and potentially throwing away money.


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## GOGOVDUBER (May 22, 2001)

*Re: HeLp: P0440 code and passing smog (bearing01)*

i checked the evap purge valve and its ticking not buzzing. does it mean its working cause i hear really fast ticks? man i can't believe that little valve piece is a $100.


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## Neckromacr (Aug 1, 2002)

*Re: HeLp: P0440 code and passing smog (bearing01)*


_Quote, originally posted by *bearing01* »_
16824	P0440	EVAP Emission Contr.Sys. Malfunction
This should be an easy fix. It's the component that stores all the gas tank fumes in a carbon canister and after the car is started a solenoid controlled purge regulator cuts in and lets the gas fumes get sucked/burned in the intake. on the top-back side of the throttle body there is a black hose around 1/4" diameter. Follow that guy over toward the passengers side of the engine bay and it should hook into a donut shapped piece just behind the air filter box (this is the solenoid-purge regulator valve). Chances are this valve is stuck open or not coming on. When the car is warmed up and running if you touch this valve with your fingers you should feel it buzzing. If it is then it's working properly. If this valve gets unplugged for some reason or is faulty then you will get the P0440 code.* With the sensor unplugged you can measure the resistance between its contacts. The valve should have some finite resistance and not open circuit.* If it is open circuited or not buzzing then replace this valve. It shouldn't cost too much... under $20?
Good luck,
John

I know I'm bumping this from the dead, but I'm trying to diagnose the same code on my car. How much is "finite resistance"? I'm reading 23.7 ohms off the valve, is that excessive? Power going to the sensor is good at 7.23V
Its hard to tell if its buzzing or clicking at all, is it supposed to be loud or very obvious. My poly engine mounts transmit a lot of vibration so its hard to tell especially it the action is subtle.


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (Neckromacr)*

The engine has to be running to do these tests and should be off-idle.
You should feel it cut in and buzz every 30 seconds or so for a duration maybe 30 seconds. If you had a mechanics stethescope up to it you would hear it tick very clearly. If you put a vacuum gauge on it you would see vacuum being pulled whenever it starts to tick.
Finite resistance is any number that isn't off the mutlimeter scale. I don't know what it should read but 25 Ohms or so sounds reasonable.


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## Neckromacr (Aug 1, 2002)

*Re: HeLp: P0440 code and passing smog (bearing01)*

Thank you, I was just trying to get a range for what it should be. I'll see if I can get my hands on a mechanics stethoscope and something to read vacuum tomorrow.


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (GOGOVDUBER)*

I have the same problem. Mine is also ticking for 30 sec on/off (not "buzzing"). Is it really supposed to buzz? I ask because maybe if it is jammed it would tick instead of buzz. What do you think? Thanks guys!


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

It doesn't matter if it's ticking or buzzing... as long as you're getting vacuum while it's ticking.


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (bearing01)*

How do you know if youre getting vacuum?


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

Unplug the EVAP purge valve hose that goes to the carbon canister. Plug a vacuum gauge into that. When running and the valve starts ticking/buzzing you should see vacuum being drawn by the valve (sourced from the throttle body). I guess you could just put your finger over the hole to see if it sucks.. but the gauge is the better way to see how much vacuum you're drawing.


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (bearing01)*

OK, I went to the friendly local dealership (not sacrasm - They are pretty cool to do-it-yourselfers) He said the part is #N80 and a whopping $153, but there's and easy check. He said it can click like it's working, but still be shot. The way to tell is to take the old one off and blow through it both directions, if you can blow through both sides of it then it's bad. You should only be able to blow one direction through it and not the other.


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

I dont think it was the valve. I couldnt blow through it either way resistance measured 24... Same with a new one. Guess I'll keep looking. Let me know if anyone has ideas.


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## bearing01 (May 27, 2004)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

Maybe the wires from the ECM to the purge regulator have high resistance or corrosion?
One of the pins in the purge regulator should have either 5V or 12V on one of the two pins (using engine as your voltmeter ground reference point). During operation that voltage should stay around that value (when it's drawing current).
Is there high resistance in the wires from the ECM? Find which wires are for the purge regulator at the ECM connector. Unplug the purge regulator. Unplug the ECM connector. Find the resistance between the two purge regulator wires at the ECM connector. Should be infinite (off the scale). Now find something like a paper clip and insert that into the purge regulator connector to short both wires at the regulator. Re-measure the resistance at the ECM connector. Should be near zero ohms when using the lowest resistance scale. If the wires check out fine then ? Do you have a good friend with a similar car to test your purge regulator on?


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (bearing01)*

You'll have to excuse my ignorance I don't know right off-hand where these wires are, but I get the concept. That's a very good idea! I'm going to replace the gas cap (it's cheap) and check my charcoal canister (just in case). If the code doesn't go away I'll try to find the path between ECM and regulator.


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## questorz (Feb 3, 2008)

*Re: HeLp: P0440 code and passing smog (GOGOVDUBER)*

Bumping from the dead.. 
I have the non-cool 0440 EVAP code also. 
I can clear my 0440 code. I then drive about 10 miles and all the readiness bits except the EVAP displays OK. The engine light isn't on yet (at this point). Does anyone know if this will pass NC OBDII for an inspection sticker with just this one EVAP readiness code in an inconclusive state? I want to fix this problem but can't afford the pump right now (if that's it). Going to test the EVAP valve tomorrow. I replaced most of the vacuum hoses... Have limited time and just want to get a sticker before the $125.00 fine.


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (questorz)*

I doubt it will pass if every catagory is not "ready" and they won't be ready if there is a code present. I'm giving up on mine and taking it to a shop to be smoketested for leaks.


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

OK, so, I go tthe smoke test....







It was the freaking purge selenoid! I took it out three times!!! It clicked, it sucked, and it passed the multimeter test.
But, the smoke test revealed that it was leaking anyway.


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## questorz (Feb 3, 2008)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

Mine actually passed! I cleared the 0440 code, drove until all the bits were OK except for the EVAP which was inconclusive. At this time the CEL had not come back on. The shop I was at didn't say a word to me about it. I finally got around to testing the purge valve and it was not running, clicking, etc. Tested with a meter and it had infinite resistance...
Anyone got a used working one they could sell me for a good price??? Looks like I will have to pay the $$ and get it over with. 









_Modified by questorz at 11:41 AM 3-2-2008_


_Modified by questorz at 11:42 AM 3-2-2008_


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## the velvet buzzsaw (Sep 11, 2007)

*Re: HeLp: P0440 code and passing smog (questorz)*

You can HAVE my old one http://****************.com/smile/emgift.gif if you paypal me the shipping. Everything about it appears to work it just doesn't work enough to pass the test. Mechanic says there's maybe some junk in there that occasionally jams it open when it should close off. You might be able to soak it in something and clean it out or something.


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## questorz (Feb 3, 2008)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*

Thanks for the offer. I really want to buy one that's known working 100%.


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## mschaef114 (Mar 13, 2008)

*Re: HeLp: P0440 code and passing smog (questorz)*

I have the exact same code and tried the touch test. I couldn't feel any buzzing or ticking. I pulled the valve leading to the canister and was able to get some suction. At first I thought this was working but then I swapped the valve with a used one from the salvage yard. The difference in suction was considerably different. 
I wouldn't hesitate to try one from the salvage yard first. Sure beats spending $115 for a new one.


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## questorz (Feb 3, 2008)

*Re: HeLp: P0440 code and passing smog (mschaef114)*

Unfortunately it seems all my local salvage yards have crushed year models 2000 and back due to metal prices being so good.


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## 2low4fathoes (Apr 25, 2006)

*Re: HeLp: P0440 code and passing smog (questorz)*

i cant get my car to start to even check to see if that is my prob... the valve issue. but my car took a puddle on and drove like junk on the way home. echeck engine light came on blinking.


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## roy.vanegas (Jul 24, 2008)

*Re: HeLp: P0440 code and passing smog (the velvet buzzsaw)*


_Quote, originally posted by *the velvet buzzsaw* »_OK, so, I go tthe smoke test....







It was the freaking purge selenoid! I took it out three times!!! It clicked, it sucked, and it passed the multimeter test.
But, the smoke test revealed that it was leaking anyway.









by "purge solenoid" do you mean the "purge regulator valve"?
regarding your leak, do you know exactly where that leak was?
thanks,
roy


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## Submit Withdrawal (Nov 23, 2008)

*Re: HeLp: P0440 code and passing smog (GOGOVDUBER)*

I have had a similar issue with a P0440 check engine light on my 1996 VW Golf VR6 2.8L. I took it to multiple shops who told me it was a gas cap. When I bought one new from the dealer the CEL came back on. So, with a little research I found that the code was an "Evap System Malfunction" which does not even relate to the fuel cap, as it has its own separate code. So, I kept looking and found that the purge regulator valve could be at fault. Without a manual there was no way to determine if it was faulty. However, forums suggested that it should feel or sound like it's "clicking" on and off when the engine is warm. My regulator valve was not clicking, vibrating, or showing any signs of movement, so it was replaced for about $100.00 from some vendor online. The code got flashed but still came back. 
After I purchased a new Bentley manual I decided to check the whole system. The evap system is designed to pull excess fuel vapors back into the engine to be burned. It runs from the fuel tank to the engine bay where it meets the solenoid that activates a valve opening or blocking off the vacuum sucking the vapors back into the engine. From the valve it moves through a charcoal canister mounted below the airbox and back into the intake manifold. 
I ended up dropping the fuel tank to check the lines for damage or other problems and found was plugged by fuel. If you look under passenger side of the car you will see 3-4 hard plastic fuel lines running parallel to each other. I found that some fuel had collected at a low point in the clear evap line and looked like it was plugging the vacuum. We pressurized all of the lines in the system to clear any obstruction and check for leaks. We then reassembled the car and the check engine light went away... for two months.
Now that CEL is back on again with the same code! This is getting ridiculous because the Bentley book has not been helpful in troubleshooting and correcting this issue. 
I'm going to check the system for leaks and plugs again and re-check the solenoid valve (new,) the gravity valve in the tank (new,) and the charcoal canister (original.) If I don't find any problems I will have to check to make sure there isn't a problem with the electrical system. We checked the valve by passing 9 volts through its terminals and it clicked open. However, the car only pushes 6-8 volts to the valve. If that amount of power is not enough to actuate the solenoid, then we'll have to dig into the harness and find out what is causing the voltage drop.
I'm not a certified mechanic, so I hope that I'm troubleshooting this problem the right way. The problem is that I'm still not 100% confident that I'm looking at the system and the problem correctly. If one of you know more about this than I do *or if it looks like I'm taking this in the wrong direction, please chime in!*
-Rich


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## Submit Withdrawal (Nov 23, 2008)

*Re: HeLp: P0440 code and passing smog (Submit Withdrawal)*

I checked out the Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80) last night. With my hand, it felt like it was not clicking or buzzing while the car was warming up in my garage. So, I disconnected it and checked voltage at the connector. It looks like it's getting 6.8x volts on a constant supply. However, what I found was weird was that the voltage only fluctuated between 6.83-6.88 volts. If the engine was sending power to open the valve, I would expect to see the current spike. However, the power did not ever make a dramatic change.
I'm guessing that there might be a problem with the electrical system on the car. If the valve needs a spike to get it opened and the car is not sending it, what systems could be causing the issue and how do you go about fixing it?
My bentley manual showed that the power comes straight from the ECU. So, would I have to have my ECU reprogrammed to correct this issue or could it be another system that's causing the problem?
Can anyone confirm or deny that the voltage I'm getting is enough to open the valve?
Any help is appreciated!


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## Submit Withdrawal (Nov 23, 2008)

*Re: HeLp: P0440 code and passing smog (Submit Withdrawal)*

Today I went to see a specialist at Mobile One Inc in Glenview, IL. The mechanics there were knowledgeable and precise, but the solution to the problem still seemed to evade them. 
They tested the EVAP system by passing smoke through it to check for leaks. When it came up OK they tested the (N80) Purge Valve with the VAGCOM and it clicked on and off with the ECU as expected. BEWARE! Apparently there are three different (N80) Purge Valves designed for the 1996 VR6. Some of the valves rest open and will click shut with the ECU while others will rest closed and click open with the ECU. After some research they found that the new valve I bought online was the correct one, thankfully. 
With further testing they found that my throttle body would not cycle through positioning with the computer. They think it might be dirty, so they want to clean it out and re-test. Because the problem did not show up on the scanner, it is possible that the ECU is throwing a false P0440 code. If we clean and recalibrate the throttle body they might correct the code, in theory. We also confirmed that the charcoal canister was moved from the passenger to the driver's front wheel well. It's possible that the added 10'-15' of lines might interfere with the vacuum, so we'll probably get that back to the right spot before the car goes back into the shop. 
Any thoughts?


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## psparky (Dec 29, 2008)

*Re: HeLp: P0440 code and passing smog (Submit Withdrawal)*

Hey Submit, Would like to here update on your problem. I had the MIL light come on and scanner showed lean engine code and I replaced leaky vacuum line and reset OBD. 400 miles later I got a pending code of P0440 and system still had not completed all the readiness tests and then at 600 miles I got MIL light on dash. Have not read OBD yet but think it got ready and light came on. Have not looked further yet but certainly will start around purge valve, anxiously awaiting your results.

_Modified by psparky at 12:40 PM 12-29-2008_


_Modified by psparky at 12:43 PM 12-29-2008_


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## psparky (Dec 29, 2008)

*Re: HeLp: P0440 code and passing smog (psparky)*

Read the codes and I had a lean engine, P171 and a Evaporative Emission malfunction, P0440. Found that the aircleaner was unsnapped and put that on correctly. My purge valve never made any noise so I replaced that and maybe the connector is bad on harness. The valve started ticking with each tick registering on vacuum gauge on line T to manifold. The pulsation in vacuum, about +/- half inch mercury coincided with each tick, it was probably about 4or 5 times per second. But when wiggling the connector it would stop and start so I am replacing connector on harness with another. It looks like same connector as on the injectors.


_Modified by psparky at 10:27 AM 2-20-2009_


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## psparky (Dec 29, 2008)

*Re: HeLp: P0440 code and passing smog (psparky)*

Replaced harness connector on purge valve and ran a scan which said all was good but catylst was not ready. Local mechanic said take it for a freeway ride at 60 mph and the catylst would get ready so I took it for a fifty mile ride on the highway and bingo, all readiness tests complete, no trouble codes no pending codes. I am off to DMV on Monday morning, wish me luck.
Failed inspection for gas cap problem, I had no code (P0441) for that anyway went and bought one for $10 and back to DMV and I passed.

_Modified by psparky at 12:16 PM 2-23-2009_


_Modified by psparky at 9:48 AM 3-19-2009_


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