# What is N249?



## heysuperman (Aug 17, 2002)

running a forge DVR. got a code for it accidentally erased so i can't tell ya what it is. but what is the N249


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## JTwGTI (Sep 25, 2003)

*Re: What is N249? (heysuperman)*

Its the sensor that controls the DV. If it was a 'mechanical faliure' code, then your Forge may have been acting nutty, but if it was an electrical malfunctional or failure code, then you need to check the N249 itself. Likely mechanical. http://****************.com/smile/emthup.gif


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## tim18t (Feb 1, 2003)

*Re: What is N249? (JTwGTI)*

that is jibberish for something you dont really need and can do without, just bypass it and run the dv line straight to the manifold where the 249 is plugged in now http://****************.com/smile/emthup.gif


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## GTI 2744 (Feb 1, 2003)

*Re: What is N249? (tim18t)*


_Quote, originally posted by *tim18t* »_that is jibberish for something you dont really need and can do without, just bypass it and run the dv line straight to the manifold where the 249 is plugged in now http://****************.com/smile/emthup.gif 

what would that do? i wouldn't want anything that controls my DV possibly failing....if i bypass this what kind of codes would come up if any?


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## heysuperman (Aug 17, 2002)

*Re: What is N249? (GTI 2744)*


_Quote, originally posted by *GTI 2744* »_
what would that do? i wouldn't want anything that controls my DV possibly failing....if i bypass this what kind of codes would come up if any?

good question. anyone know?


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## feuerdog (Feb 11, 2002)

N249 - Diverter Valve Control Solenoid
The N249 is a valve that controls the vacuum/boost signal to the DV that tells it when to open,....basically.
When you change your DV there is a possibility of getting this N249 mechanical failure code,.......I get it all the time, mainly because I am using an aftermarket bypass valve.
The N249 costs about $180 bucks, and is about the size of the N75. It's small. It's located near the front of the engine, under the smaller plastic cover, and in connected to the vac./boost hose that is connected to the back of the DV.
Itwill probably be a recurring soft code for you as long as you run that DV. But it does not mean that the N249 is actually broken.
Put your stock DV back on to confirm this.











_Modified by feuerdog at 12:00 AM 3-3-2004_


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## heysuperman (Aug 17, 2002)

*Re: (feuerdog)*

this is what i pulled off my palm pilot running prodiag:
17608: Recirculating Valve for turbocharger -N249: mechanical malfunction
i'm wondering if it's because it's in backwards. that's the way forge says to install it, but it isn't the way the factory had it. i'll pop back the stock one and see what it does.


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## heysuperman (Aug 17, 2002)

*Re: (heysuperman)*

called forge. they suggested i step back down to a softer spring. gonna give that a shot


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## feuerdog (Feb 11, 2002)

*Re: (heysuperman)*

The Forge valve you have is the Diverter Valve.
The Diverter Valve is a recirculating valve(bypass valve).
The N249 valve is a solenoid, and is a different piece alltogether,.....but it is connected to the DV via a vac./boost hose.
*The DV and N249 are two different parts, on different sides of the engine.*


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## heysuperman (Aug 17, 2002)

*Re: (feuerdog)*


_Quote, originally posted by *feuerdog* »_The Forge valve you have is the Diverter Valve.
The Diverter Valve is a recirculating valve(bypass valve).
The N249 valve is a solenoid, and is a different piece alltogether,.....but it is connected to the DV via a vac./boost hose.
*The DV and N249 are two different parts, on different sides of the engine.*









yeah, i know what a dv is. i understand what the n249 is and what it does. forge believes the n249 is saying that the DV isn't opening properly. as i state they suggested going to a softer spring than i had installed. haven't gotten home to give it a shot yet, but i will here in a bit.


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## evilpat (Feb 26, 2002)

*Re: (heysuperman)*

Follow the red line
















Bypass that thing while your at it.


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## hugemikeyd (Aug 28, 2001)

*Re: (evilpat)*

the N249 is NOT neccessary for engine use, its an ECU controlled vaccum source so the ECU can pull back boost if the N75 fails. You can bypass it and run it off of an intake manifold vac source and be fine. In fact that may be smooth out your boost delivery


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## ben99 (Jun 16, 2003)

*Re: (evilpat)*


_Quote, originally posted by *evilpat* »_Follow the red line
















Bypass that thing while your at it.

If I bypass the N249 and just run a hose from the manifold to the DV, then do I just plug up those unused ports on the N249, but leave the electrical plug plugged in. What about the other items in the diagram that run off of that same vacuum port off the manifold (#'s 16, 18, 12, 13, 20 on the diagram)?


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## evilpat (Feb 26, 2002)

*Re: (ben99)*

Easiest way to do it would be to cap off the line on the top of the DV and just T into the vacuum line under the manifold. Or, if you are feeling creative you could cap off that red line right after the N249 (or at the 3-hose bracket under and on the right of the black bracket on the front of the manifold and run a line to there and retain the vacuum hose to the DV).
Your call http://****************.com/smile/emthup.gif


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## heysuperman (Aug 17, 2002)

*Re: (evilpat)*

problem solved. it was just the spring i had in the DVR


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## feuerdog (Feb 11, 2002)

*Re: (evilpat)*


_Quote, originally posted by *evilpat* »_Easiest way to do it would be to cap off the line on the top of the DV and just T into the vacuum line under the manifold. Or, if you are feeling creative you could cap off that red line right after the N249 (or at the 3-hose bracket under and on the right of the black bracket on the front of the manifold and run a line to there and retain the vacuum hose to the DV).
Your call http://****************.com/smile/emthup.gif 

I assume that this will stop the ECU from throwing N249 codes?

Anyways,....I can't do this bypass. I am running a HKS SSQ in a recirculating mode, and it needs a signal to open the two-stage valve.
Is there another way to send a signal to the DV(HKS) and still bypass the N249?


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## evilpat (Feb 26, 2002)

*Re: (feuerdog)*

In theory it will prevent the ECU from throwing an N249 code due to the DV.
Don't understand why it wouldn't work with your HKS though??? Bypassed the signal is still exactly the same (smoother for a lit of people with AWW & AWP) as before except that you are removing the ECU's control over the DV (or BOV in your case).


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## feuerdog (Feb 11, 2002)

I'm running my bosst gauge off of the boost line that goes to the back side of the FPR(I am aware of the dangers of this btw), is that the same hose/signal?


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## hugemikeyd (Aug 28, 2001)

*Re: (feuerdog)*


_Quote, originally posted by *feuerdog* »_Is there another way to send a signal to the DV(HKS) and still bypass the N249?

the N249 is an ECU controlled vac line, cap off the input to the DV and grab a vac source elsewhere. Its the same thing except now your DV is running off of the vac line and its turbo controlled rather than ECU controlled


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## ::..BoraXTC..:: (Oct 16, 2003)

will you through a code if you unplugged the n249?


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## hugemikeyd (Aug 28, 2001)

*Re: :..BoraXTC..:*


_Quote, originally posted by *::..BoraXTC..::* »_will you through a code if you unplugged the n249?

electrically, i believe so, if you left it plugged in and plugged up the vac hose that goes to the DV it should be fine as long as you have a stock turbo and are not exceeding the ECU's boost expectations.


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## ToUcH n Go (Dec 22, 2006)

*Re: (hugemikeyd)*

I am wondering if this P1200 N249 Mechanical Malfunction code is one that the ECU throws out hard, IE, will cause the CEL to illuminate?
Reason I ask is I have other coilpack issue codes being thrown at the same time, and i am wondering if the light is a result of this N249 code or the coilpack codes that I never erased when replacing the coil pack fault...


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## 18T_BT (Sep 15, 2005)

*Re: What is N249? (GTI 2744)*


_Quote, originally posted by *GTI 2744* »_
what would that do? i wouldn't want anything that controls my DV possibly failing....if i bypass this what kind of codes would come up if any?


_Quote, originally posted by *heysuperman* »_
good question. anyone know?

you'll know if you don't hear your PSSSSSSSSSSSSSHHHHHHHHTTTT...FYI on older audi's that were turbo charged from the factory, they didn't have any noise makers aka DV's on their cars even stock...so, it's not an absolute MUST, just prevents the turbo of failing quicker, that's all...


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## Maxpowerz (Feb 9, 2004)

*Re: (ToUcH n Go)*


_Quote, originally posted by *ToUcH n Go* »_I am wondering if this P1200 N249 Mechanical Malfunction code is one that the ECU throws out hard, IE, will cause the CEL to illuminate?
Reason I ask is I have other coilpack issue codes being thrown at the same time, and i am wondering if the light is a result of this N249 code or the coilpack codes that I never erased when replacing the coil pack fault...

no when i had the N249 code the CEL does not turn on


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## sys3175 (Jan 26, 2004)

*Re: (evilpat)*

Lol.. I have a AWW.. however it is an automatic.. and I can tell you bypassing the N249 is no fun in this situation. Heading down the highway after bypassing it, coming up to traffic.. I was doing about 75 at about half throttle.. traffic was at a stop.. I get off the throttle and the car just keeps going..







Had to drop it into neutral because it started to overheat my brakes. N249 is good on an auto. LOL.

_Quote, originally posted by *evilpat* »_In theory it will prevent the ECU from throwing an N249 code due to the DV.
Don't understand why it wouldn't work with your HKS though??? Bypassed the signal is still exactly the same (smoother for a lit of people with AWW & AWP) as before except that you are removing the ECU's control over the DV (or BOV in your case).


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## zeusenergy (Feb 25, 2008)

*Re: What is N249? (18T_BT)*


_Quote, originally posted by *18T_BT* »_
you'll know if you don't hear your PSSSSSSSSSSSSSHHHHHHHHTTTT...FYI on older audi's that were turbo charged from the factory, they didn't have any noise makers aka DV's on their cars even stock...so, it's not an absolute MUST, just prevents the turbo of failing quicker, that's all...

Yes, prevents failure of turbo. Also prevents hose blowouts from 40+PSI conditions when the throttle slams shut, keeps the turbo spooled up and prevents turbo lag like the older audis and other turbo cars had in spades. Overboosting my old 5000 TQ blew the charge hot side hose off my turbo, and also made my TB cold side hose blow up. Adding a DV stopped this from happening and made the thing way more reponsive.


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## veeko (Oct 26, 2005)

*Re: What is N249? (zeusenergy)*

could having the 'Boost Pressure Control Valve (N249): Mechanical Malfunction' code cause any issues with idle?


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## zeusenergy (Feb 25, 2008)

*Re: What is N249? (veeko)*

nope. The DV just isn't relieving boost like the ECM expects. Idle should not be a consequence unless one of the small vac lines in the rats nest around the N249 or DV is broken or cracked.


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## 5inchMAF (Sep 12, 2007)

*Re: What is N249? (veeko)*


_Quote, originally posted by *veeko* »_could having the 'Boost Pressure Control Valve (N249): Mechanical Malfunction' code cause any issues with idle?

i want to know this too.

i took my vacuum reservoir off and i got a code for it (not a full CEL. but when getting a new BT file from revo, he saw it). the code was for the n249. what is the relationship between the vacuum reservoir and the n249?


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## veeko (Oct 26, 2005)

*Re: What is N249? (zeusenergy)*


_Quote, originally posted by *zeusenergy* »_nope. The DV just isn't relieving boost like the ECM expects. Idle should not be a consequence unless one of the small vac lines in the rats nest around the N249 or DV is broken or cracked.

thanks http://****************.com/smile/emthup.gif


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## JettaRed (Aug 14, 2000)

*Re: (sys3175)*


_Quote, originally posted by *sys3175* »_.. I get off the throttle and the car just keeps going..







Had to drop it into neutral because it started to overheat my brakes. N249 is good on an auto. LOL.


Don't know how that would happen. I have a '99 A4Q that does not use the N249. The DV connects directly to the intake manifold. 
If that happened, I suspect you had a serious vacuum leak from a probable installation mistake. Plus, what happened when you put it in neutral? Did the car over-rev?


_Modified by JettaRed at 11:18 AM 5-5-2008_


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## InstantKarma (Jan 5, 2005)

*Re: (JettaRed)*

noone seems to understand that if you delete your n249 then any time there is vacuum in the intake manifold the DV/BOV will be wide open. including idle.
this means that when you are accelerating and your vacuum is still below 0, the air is being sucked backwards through your DV instead of through the turbo. so that ends up creating slower spooling.
the really big downside to this is if you run a BOV. because at idle or any time you are accelerating (without being wide open throttle) air is being sucked backwards through the BOV. *unfiltered air from the engine bay. * 
I had mine unplugged for a long time, just running my dv off the intake manifold. but every time i take off from a stop light i can hear the air being sucked backwards through the valve. I have since then put the n249 back in and it cleared up a few codes that were randomly showing up like pressure drop and positive deviaton.


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## InstantKarma (Jan 5, 2005)

*Re: (Cass944)*

i have tested all the springs that forge sells with their 007 dv and all of them are wide open at between 12 and 14 hg vacuum. your intake manifold usually pulls 20hg at idle. so if you have a boost gauge in your car watch it and see how often the valve will be being pulled open when you wouldn't want it to.
its mostly when accelerating slowly. wide open throttle should close it right away because as soon as there is boost in the manifold the boost will hold the valve shut.
it is also very noticeable during highway cruising. if your in 5th gear and your cruising and you goto slowly accelerate a little, the should of air being sucked backwards through the dv will be extremely noticeable.


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## vdubN228 (Aug 14, 2006)

would the the code show for even the audi 225 hp dv?


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## InstantKarma (Jan 5, 2005)

*Re: (vdubN228)*

i have no idea. all i know is that all intake manifolds and DV's work the same way.
technically you shouldnt really get any codes from doing this... because even though air is being sucked backwards through the DV, it is still air that has passed by the air flow meter. your pretty much just bypassing the turbo and going straight to the charge pipe.
if anything the only codes you might see are pressure drop codes just because the turbo is going to spool slower at first just because most of the air that should be flowing through it is now being rerouted through the DV.
if you have a BOV its a completely different story though. because then air that has NOT passed through the air flow meter will be entering the charge pipe. and the car will run super lean while accelerating. 
so if your going to run a BOV at least do it with the n249 hooked up


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## zeusenergy (Feb 25, 2008)

*Re: What is N249? (BIGGEE TALLS)*

Vac reservoir allows the DV to open if the ECM wants it to, regardless of the boost/vac condition at the manifold. Normally if the ECM wants to dump boost levels- it can do so in three main ways. 
1)Drop the throttle plate
2)ECM stops using the N75 duty cycle (deactivates it, 0%) so that the WG will remain open fully
3)Activate the N249 to suck the air out of the DV by means of the reservior, opening it up
The N249 on my car is attached to the charge pipe, so the top of the DV sees only pressure normally. When the ECM tells the N249 to open up, it allows the vacuum from the reservoir a path to the top of the dv. Your car may have the normally open port attached to the manifold itself (MK4) so it might see vac sometimes anyway, regardless of the N249's state. On my car the N249 connections ONLY allow vac under an active condition of the N249. In effect, if the N249 failed on my car and a runaway boost condition occured because I bypassed N75 and went with DBC, then there would be no way for the ECM to control it any longer.
Right now with N75 and N249 bypassed, only the DBW throttle can hold me back. And it DOES, over 14.5 PSI and no diode attached.








BTW, there is something to the N249 bypass having an effect on lag or onset of boost.... I get this symptom now, although minor and really it's better than stock, where the ecm wants to rid me of the boost I worked so hard to create and hold!
The code for mech failure in N249 circuit has to do with the ECM not seeing an effect after attempting to drop boost via the N249, which will happen after an N249 delete, heavy-spring DV, or removed reservior.


_Modified by zeusenergy at 7:58 PM 5-5-2008_


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## InstantKarma (Jan 5, 2005)

*Re: What is N249? (zeusenergy)*

yeah your setup is a little different on the beetle. The n249 is never hooked to the charge pipe in any way. instead they hook it to the manifold and stick a couple one way valves in there.
works pretty much the same way.


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## Zweibb (Jun 6, 2006)

*N249 Recirculating Valve for Turbocharger*

Having intermittent stuttering/hesitation of the engine when starting out in 1st gear and hard acceleration in 3rd gear. Replaced OEM diverter valve with a "Forge" unit Fault Code 17705/P1297, replaced spark plugs and coil packs Fault Code 16684/P0301 and 16686/P0302, replaced spark plug/coil pack wiring harness (check/cracked insulating cover), notice oil leak in spark park wells and replace valve cover gasket plus PCV valve. Verified ohm reading of N249 registering at 22.5 Ohm below recommended 27-30 Ohms. I have notice threads indicating changing the spring pressure in the diverter valve not sure if this will correct/address the engine hesitation knowing the resistance on the recirculating valve (N249) is out of spec. Comments please.


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## Slimjimmn (Apr 8, 2006)

blowing some more dust off threads i see ....:facepalm:


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