VAGCOM 16825 P0441 fault code. Any quick fix?

[farcrygamer]

Hi guys,

I scaned my octy this morning with vagcom.

The reading was:

1 Fault Found:

16825 - EVAP Emission Control Sys: Incorrect Flow

P0441 - 35-10 - - - Intermittent

Readiness: 0000 0000

------------------------------

The car feels fine. It's strong and pulls really well. Mods wise it's got remap, piperx filter, smoothed drilled airbox, forge 007p with yellow spring( recently serviced) , denso ik 20 plugs.

How serious problem is this?

Can anyone suggest a possible diy fix for this problem?

Any help gratefully appreciated

Cheers

Igor

Edited 6 October, 2008 by farcrygamer

[rwbaldwin]

There is a charcoal canister that sits between the coolant expansion tank and the power steering reservoir.

First thing I'd check is the connector to the purge valve has not come loose.

[farcrygamer]

There is a charcoal canister that sits between the coolant expansion tank and the power steering reservoir.

First thing I'd check is the connector to the purge valve has not come loose.

Thank you very much:thumbup:

Just checked that and it's all fine.

The fault code is still there:mad:

Cheers

[rwbaldwin]

Do you get a hiss when you open the petrol filler cap?

[farcrygamer]

Do you get a hiss when you open the petrol filler cap?

Haven't noticed that to be honest. I 'll try to pay more attention to tomorrow.

Cheers

[Tech1e]

Do you brim the fuel tank when filling up?

Sounds like the N80 valve is faulty in the top of the canister. A final control diagnostic test would check its operation.

[rwbaldwin]

No long hiss (you would notice) so I would suspect that the purge valve is stuck open. The valve can be prised out quite easily. Not sure if it can be cleaned, but it must be worth a look to see if it's jammed rather than completely gone

[farcrygamer]

Thank you so much for that guys

Does anyone have a photo of those valves or a direction on how to recognize them?

What i did notice is when i squeeze the tubing that connects the carbon canister and the purge valve there is some kind of hiss noise in the canister.

The connection between that tubing and canister seams to be fine as well as the one in the bottom where the purge valve is.

Is that risky for the car? Is it safe to drive with this problem at all?

Cheers

Igor

[farcrygamer]

Does anyone have a part number for n80 valve please?

[farcrygamer]

a bit old thread :-). I swapped the n80 and the fuel cap. it was fine till now and it came on again. no hissign from fuel tank. tested the n80 and came out fine. connections around the charcoal can all look fine. any other suggestions?

[Gizmo]

A couple of other options for you to look at:

16825/P0441/001089 - EVAP Emission Control Sys: Incorrect Flow

Possible Symptoms

• Malfunction Indicator Light (MIL) active

Possible Causes

• Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80) faulty/jammed
• Evaporative Emission (EVAP) Canister Purge Solenoid Valve (N115) faulty/jammed
• Evaporative Emission (EVAP) Canister Sealing faulty
• Pipes between Tank Breathing and Throttle Body leaky/blocked

Possible Solutions

• Check Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80)
  • Perform Output Test

  [*] Check Evaporative Emission (EVAP) Canister Purge Solenoid Valve (N115)[*] Check Evaporative Emission (EVAP) Canister

  • Perform Basic Setting

  [*] Check Pipes between Tank Breathing and Throttle Body

[rk696]

IS the chacoal canister ticking when the engine is warm?

[farcrygamer]

The N80 (valve on top of the canister itslef) is been replaced so it shouldn't be problematic. the pipework between the tank breathing and the throttle body look ok, throttle body has been cleaned, seal replaced and properly torqued. the canister ticks when the car is warming up but it does not tick when the engine is at optimal temp as far as i noticed. i do not know where the n115 is? could you guys suggest what valve is that one and where is it?

[rwbaldwin]

When were the bits replaced? Recently or in October 2008?

[farcrygamer]

the n80 was replaced in oct 2008 but the car has covered less than 20k since then. i checked the n80 yesterday and it ticks fine when warm. t-body was cleaned, the whole pcv system and all pressure hoses were replaced with silicone ones last summer (less than 10k back). I don't know yet where that n115 is. After i clear the codes with VCDS and allign the t-body the cars restores the power and gets fairly fast again. but after a while the code appear again and the car gets a little more sluggish (still not slow at all but not as responsive as it should be).

Edited 29 June, 2011 by farcrygamer

[rwbaldwin]

Don't bother looking for the N115. IIRC, it's NAR only, so you don't have one.

If you don't hear a hiss when you open the fuel cap, then the vapours are going somewhere. This is usually the N80, but it can be a faulty canister, a leaking vent line or seal. Can you smell petrol around the canister or anywhere else?

If you were to get a hiss, then it could be a faulty vent valve at the tank or a blocked vent line.

There is an outside chance it is a fault with the front lambda sensor. The ECU monitors the change in lambda to detect correct flow. I have only ever seen this once. It would be very unusual for the sensor to be faulty but not throw up a code.

[farcrygamer]

I really tried to smell petrol around the canister area buti simply couldn't. The canister cap was also replaced last year together with the pcv system and boost hoses. No hissing definitely when i open the tank. fuel trims also seem fine by vcds logging. the vent line i i suppose the one that goes from the fuel tank all the way to the engine bay and into the carbon canister, isn't it? and i also suppose the seal you mentioned should be the seal on a carbon can. On friday will go to a local friendly garage who will let me lift up the car and inspect the fuel tank vent lines so i really hope to find the root cause of this ultra annoying problem. is there any test for the canister seal? i don't really fancy buying a new canister and still have the same bloody code on :-) . thanks a ton for helping me out with this

[rwbaldwin]

Use a Mityvac or similar to check the N80 - just because you can hear a noise doesn't mean it's closing correctly.

Check the vent line by pulling a vacuum on the vent line without and then with the fuel cap. In both cases a vacuum should not build up. If a vacuum is created without the cap then look for a blocked vent line or faulty vent valve. If a vacuum is created with the cap, then try replacing the cap. Best to do the tests with a full tank of gas.

If you put your finger over the hose that connects to the N80 outlet you should feel the engine sucking.

Apply gentle air pressure from the Mityvac to the canister via the input hose to the canister. It should hold pressure.

Let the garage disconnect the connector that joins the vent line to input hose to the canister. There is a knack of disconnecting them. Also have them check the connector.

HTH

[farcrygamer]

Thank you so much for such a great spet by step guide. I'll try to do the tests and hopefully post back with great news. i got 3 fuel caps all together so at least one will be good i hope. one is nearly new fitted last year, one is my old cap and one is a leftover from a mates golf gti. i tried them all so far with not much luck. will try with mityvac tomorrow in a garage and see what it discovers :-) Cheers

Use a Mityvac or similar to check the N80 - just because you can hear a noise doesn't mean it's closing correctly.

Check the vent line by pulling a vacuum on the vent line without and then with the fuel cap. In both cases a vacuum should not build up. If a vacuum is created without the cap then look for a blocked vent line or faulty vent valve. If a vacuum is created with the cap, then try replacing the cap. Best to do the tests with a full tank of gas.

If you put your finger over the hose that connects to the N80 outlet you should feel it sucking.

Apply gentle air pressure from the Mityvac to the canister via the input hose to the canister. It should hold pressure.

Let the garage disconnect the connector that joins the vent line to input hose to the canister. There is a knack of disconnecting them. Also have them check the connector.

HTH

Edited 30 June, 2011 by farcrygamer

[farcrygamer]

Just a little update on the case :-) Here are my findings so far :

I will go to this garage this evening to fit a high flow cat, and 2.5'' jetex exhaust as the existing factory fitted one is really knackered. hope to get some additional findings about this 16825 trouble. Thanks

Edited 1 July, 2011 by farcrygamer

[rwbaldwin]

...Check the vent line by pulling a vacuum on the vent line without and then with the fuel cap. In both cases a vacuum should not build up. If a vacuum is created without the cap then look for a blocked vent line or faulty vent valve. If a vacuum is created with the cap, then try replacing the cap. Best to do the tests with a full tank of gas...

Can you confirm that you did this test from the engine bay end of the vent line?

[farcrygamer]

Yes, That is correct. the hand pump can blow through the vent line from the engine bay and suck through it without creation of vacuum with or without the gas cap on. the vent line from the tank to the engine bay looks as good as new underneath the car with no cracks or and split points. garage guys couldn't suggest anything apart from what i've already done. they think it's the carbon canister itself that is creating a problem although it can hold pressure. Do you agree with that? any further suggestion? Cheers

Edited 4 July, 2011 by farcrygamer

[rwbaldwin]

If you prise out the purge valve after the car has benn sitting in the sun, do you get a strong smell of petrol that lingers for several minutes as it is released from the activated charcoal?

If you do, then apply 12V to the purge valve (so it is open) and try and pull a vacuum on the can. You shouldn't be able to. If you can, then the breather on the underside of the can if blocked or the can is faulty. I wouldn't rule out the N80 entirely - they can be intermittant.

If you can't smell vapours from the can, then try a new genuine fuel cap. I hope you don't press on the little valve in the filler neck to get more gas in. I've seen a few of them broken in this way. This valve could be faulty.

[farcrygamer]

Thank you so much for helping out with this.

That was the very scenario i've got in my octy. The carbon can drains breather was badly blocked as the pump managed to apply vacuum with n80 open. I got a new carbon can from the stealers. The old can was much heavier than the new one. I replaced it with the new one, cleared the codes and voila. so far so good. The car pulls way stronger now and the liveliness is fully restored. The MPG also raised from 30-32 to 34-35.

You really do know the stuff - Top Man!

Thanks a ton again.

If you prise out the purge valve after the car has benn sitting in the sun, do you get a strong smell of petrol that lingers for several minutes as it is released from the activated charcoal?

If you do, then apply 12V to the purge valve (so it is open) and try and pull a vacuum on the can. You shouldn't be able to. If you can, then the breather on the underside of the can if blocked or the can is faulty. I wouldn't rule out the N80 entirely - they can be intermittant.

If you can't smell vapours from the can, then try a new genuine fuel cap. I hope you don't press on the little valve in the filler neck to get more gas in. I've seen a few of them broken in this way. This valve could be faulty.