# p1200 - 35 - 10 - - intermittent



## DaMenace (Nov 1, 2008)

my car is not boosting right. after i hit 4500 rpm it let the boost go and stops boosting. i got a 2003 20th AE you guys think that this code might be the problem? it says is the boost pressure control valve(N249):mechanical malfuction. the other code it gave me is 16804 - catalyst system; bank 1:efficiency below threshold P0420 - 35 - 00 - -, but i think this one is because i dont have a catalyst. since that one is because i dont have it is there anyway to get that check engine light to stay off?


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## bluefox280 (Dec 18, 2003)

*Re: p1200 - 35 - 10 - - intermittent (DaMenace)*

** VW DTC 17608 (P1200) - Boost Pressure Control Valve (N249) - Mechanical Malfanction*
As for the boost situtation, electronic solenoid for the diverter valve (N249) is not damaged.
It's a mechanical error so, trace the vacuum lines starting at the DV and check the holding pressure and operation of the DV.
Is the car making a fluttering/chattering sound when you let go of throttle?
If so, the diaphram in the DV is torn and allowing air to pass by it; simply replace.
** VW DTC 16804 (P0420) - Catalyst System, Bank1 Efficiency Below Threshold*
Basically the ECU is seeing that the rear O2 sensor is thinking the catalyst isn't doing it's job correctly.
If stock catalyst, and the sensor is good, more than likely your cat is bad then.
How many miles on the car?
There's a federal emissions act for free no-cost replacement from the dealer is the catalyst is faulty under a certain mileage (100K, IIRC).
You'll need a VAG-COM to do some "sanity" checks on the sensor to see if the sensor is indeed working or its toast.
- Erik


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## DaMenace (Nov 1, 2008)

*Re: p1200 - 35 - 10 - - intermittent (bluefox280)*


_Quote, originally posted by *bluefox280* »_** VW DTC 17608 (P1200) - Boost Pressure Control Valve (N249) - Mechanical Malfanction*
As for the boost situtation, electronic solenoid for the diverter valve (N249) is not damaged.
It's a mechanical error so, trace the vacuum lines starting at the DV and check the holding pressure and operation of the DV.
Is the car making a fluttering/chattering sound when you let go of throttle?
If so, the diaphram in the DV is torn and allowing air to pass by it; simply replace.
** VW DTC 16804 (P0420) - Catalyst System, Bank1 Efficiency Below Threshold*
Basically the ECU is seeing that the rear O2 sensor is thinking the catalyst isn't doing it's job correctly.
If stock catalyst, and the sensor is good, more than likely your cat is bad then.
How many miles on the car?
There's a federal emissions act for free no-cost replacement from the dealer is the catalyst is faulty under a certain mileage (100K, IIRC).
You'll need a VAG-COM to do some "sanity" checks on the sensor to see if the sensor is indeed working or its toast.
- Erik

my car have 69000 miles and no the only noise it makes is the whoosh when i let go off the throttle.


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## bluefox280 (Dec 18, 2003)

*Re: p1200 - 35 - 10 - - intermittent (DaMenace)*


_Quote, originally posted by *DaMenace* »_...only noise it makes is the whoosh when i let go off the throttle.

Still, check it.
The ECU is seeing a serious fault. Pressurize and verify intake tract.
- Erik


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## DaMenace (Nov 1, 2008)

*Re: p1200 - 35 - 10 - - intermittent (bluefox280)*


_Quote, originally posted by *bluefox280* »_
Still, check it.
The ECU is seeing a serious fault. Pressurize and verify intake tract.
- Erik

this is something i posted on another forum that might help you help me. thanks.
the only thing that my car have is a down pipe, no cat, a different muffler, and i dont know why but is boosting 16 pounds right now. i scanned my car and the codes where cat efficiency below threshold and boost pressure control valve n249. i got 2 vw 1.8t 03 a jetta and a 20th. i've swap every valve that ppl tell me might be the problem but is not fixing the problem. i change the 2 valves that are underneath the bracket by the ntake manifold which i think is the n249 and the n112 i change the n75 and the dv valve nothing seems to work.

and another thing is it possible that my car is on limp mode for this reason?


_Modified by DaMenace at 10:44 PM 12-5-2008_


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## bluefox280 (Dec 18, 2003)

*Re: p1200 - 35 - 10 - - intermittent (DaMenace)*


_Quote, originally posted by *DaMenace* »_the only thing that my car have is a down pipe, *no cat*, a different muffler

That's the reason you're getting the P0420 code.
You need to space out what was the post-cat O2 sensor.

_Quote, originally posted by *DaMenace* »_i've swap every valve that ppl tell me might be the problem but is not fixing the problem.

Not asking you swap valves; I'm asking you to pressure check the intake. That's completely different.

_Quote, originally posted by *DaMenace* »_I dont know why but is boosting 16 pounds right now...


_Quote, originally posted by *DaMenace* »_and another thing is it possible that my car is on limp mode for this reason?

You're NOT in Limp Mode if the car is boosting 16psi+.
Limp Mode keeps you at 5psi or less...
- Erik


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## DaMenace (Nov 1, 2008)

*Re: p1200 - 35 - 10 - - intermittent (bluefox280)*

how far back do i spaced out the o2 sensor?
and if im not in limp mode why am i dumping boost so early?
could the ecu be damaged? some ppl have said that.
and how do i pressure check the intake?




_Modified by DaMenace at 9:26 AM 12-6-2008_


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## bluefox280 (Dec 18, 2003)

*Re: p1200 - 35 - 10 - - intermittent (DaMenace)*


_Quote, originally posted by *DaMenace* »_how far back do i spaced out the o2 sensor?

With eith a couple of O2 sensor foulers, or the Wayne angle block that's available.

_Quote, originally posted by *DaMenace* »_and if im not in limp mode why am i dumping boost so early?

I would not say such...
16psi isn't "dumping early". That's standard holding pressure in the higher RPM's due to a regular 1bar (14.7psi) program.

_Quote, originally posted by *DaMenace* »_could the ecu be damaged? some ppl have said that.

No, that's false testimony; especially when the ECU provides a fault code when it's shot-to-hell.

_Quote, originally posted by *DaMenace* »_and how do i pressure check the intake?

Got an air compressor, a tennis ball, and an air chuck?
* http://forums.vwvortex.com/zerothread?id=1605131
* http://forums.vwvortex.com/zerothread?id=1480495
You need to complete the leg work to determine the problem(s) at hand.
- Erik


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## DaMenace (Nov 1, 2008)

*Re: p1200 - 35 - 10 - - intermittent (bluefox280)*

what i mean by dumping early is that my car have 15 - 16 psi all the way up to 4500rpms then all the sudden it drops to 0psi. and the problem is that i got another jetta 03 1.8t and it doesnt do that.


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## bluefox280 (Dec 18, 2003)

*Re: p1200 - 35 - 10 - - intermittent (DaMenace)*


_Quote, originally posted by *DaMenace* »_what i mean by dumping early is that my car have 15 - 16 psi all the way up to 4500rpms then all the sudden it drops to 0psi.

Does the car still feel like it's pulling when the gauge reads 0psi?
If so, the gauge good be faulty.
Another way to prove such is to datalog a VAG-COM test run of measuring block 115 (spec vs. acutal pressure).
- Erik


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## DaMenace (Nov 1, 2008)

*Re: p1200 - 35 - 10 - - intermittent (bluefox280)*

no its stop pulling after it dumps


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## Luck o' the Irish (May 17, 2012)

bluefox280 said:


> ** VW DTC 17608 (P1200) - Boost Pressure Control Valve (N249) - Mechanical Malfanction*
> As for the boost situtation, electronic solenoid for the diverter valve (N249) is not damaged.
> It's a mechanical error so, trace the vacuum lines starting at the DV and check the holding pressure and operation of the DV.
> Is the car making a fluttering/chattering sound when you let go of throttle?
> ...


Bumping this from the dead because these are the 2 exact codes I have right now... as for the dv part of it.. (n249 fault code) I have an aftermarket evoms dv and it does make a chattering noise sometimes and then it will go back to the normal whoosh. I took it out and look at the diaphragm and it seems to be working fine. Could there possibly be something getting lodged in between the walls of the diaphragm? or why would it only "chatter" sometimes and act normal the other times? 

As for the p0240 I have VAG-COM lite (it was like 10 bucks for the cable and free program download) is there a way to check the sensor through the lite edition? or how else would i go about checking if the o2 sensors are good or not?


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## [email protected] Parts (Nov 27, 2006)

Confucius say no lucky day of Irish here wit-out an auto-scan.

Only take you ten minute just like food I make here in USA.

Maybe try Wanton soup with noodles mixed with duck sauce help sick car cold.

You want spicy?


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