Remap & N249 fault.

Sean_S3

Sean_S3

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I had my S3 remapped at the weekend and tonight i went out and logged air mass flow with vagcom to check things were running ok . However the readings are very low with the highest been 148 g/s at 6100 rpm. I checked for fault codes and the only one logged was :

17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction P1200 - 35-10 - - - Intermittent

Can a problem with this valve cause such a loss in power ? The car seems fine to drive with no hesitance and it certainly feels quick. Before remap i had a full service done a month ago and the diverter valve and MAF were changed when i bought the car in may.

Any help would be appreciated.
Thanks
 
Im sure I have this come up on mine every once in a while, so it must be very intermittent! Car still gives great MPG and I havent noticed any loss in power so Ive left i be. However I havent checked the air mass flow readings since having the car mapped so Ill try and get it done soon and post it on here to compare!
 
I get that error now and again also but my maf readings have always been spot on! I put the N249 error down to occaisional boost surge upsetting the valve. Clear the error and go for a hard drive and see if it comes back.
 
Thanks for the replies guys. Wrestle i cleared the faults a few times last night and it kept coming back so im guessing the extra power has seen the valve off. The guy who remapped the car seems to think that if it is dead then the ecu will use a fail safe setting which would explain why ive lost about 80bhp. I unplugged the MAF this morning for the drive to work to check that but it was the same. The car feels pretty much standard now.
 
Bypass the n249 valve then log your MAF readings, if the readings are fine then you know the n249 is shot, personaly id leave it bypassed if it works and cures the problem but some people like to keep the n249.
 
originally i had custom code stage1 mapp and i bypassed the n249 valve all was ok, now i have AMD stage2 and ever scince i have had boost droping off from 25psi to 20psi only way to get peak boost back is to disconect and reconnect the battery after 15min to reset the ecu, i have tried a new MAF new new coolant temp sensor now i have ordered a new N249 vlave which should be hear tomoz as i belive the valve maybe letting off boost as when it dosent boost properly it also takes longer to get upto boost and the car just feels sluggish so the problem you have may well be the n249, however mine dosent throw any codes
 
So you've now got the n249 connected kev?
 
yeah seemed better with the AMD stage2 with it back conected but with cc stage1 it was ok bypassed, not entirely sure it will fix my boost loss problem but i hope so as since the remap i have had about 1 1/2 weeks full boost in total so pretty fed up with it
 
Have you tried bypassing it again then just to see if it is the n249?
 
it was still bypassed from the stage1 so i reconected it and that is how i kept peak boost for the longest so far, i have the new valve on there now but need to run it for a while to see if it has fixed the boost issue
 
I had this same problem for months, where the car was overboosting because of a fault with the N249. I was having a fiddle under the bonnet :)idea:) and I swapped the positioning of the N75 valve around. Since I did that the car has been boosting perfectly. It's definitely the remap that causes these complications.
 
golf said:
I had this same problem for months, where the car was overboosting because of a fault with the N249. I was having a fiddle under the bonnet :)idea:) and I swapped the positioning of the N75 valve around. Since I did that the car has been boosting perfectly. It's definitely the remap that causes these complications.
Click to expand...

Care to share where you moved the n75 to?
 
I think he means he just turned the valve around westle, you cant move it anywhere else tbh.
 
Westle said:
Care to share where you moved the n75 to?
Click to expand...

Dani's right, I just reversed it as people often do with the N75J (even though I have the standard N75F). It might have been pure coincidence but since then the car has pulled strongly all the way to the limiter, boost comes in when it should and now it performs like a 250bhp car. Before it was overboosting massively and hitting limp mode.

I've spent double the money on petrol this week as I've been keeping it on boost and racing anyone who'll give me the time of the day. Immature and silly yes, but it's good fun!
 
Thanks. I pulled the battery last night as what ive read on here suggests it will get rid of stored faults and get rid of limp mode etc. Anyway on the way to work this morning i logged mass air and things have definatly improved. The cars making 195g/s @ 5500 rpm which is about 245 bhp as a rough estimation. The turbo sounds like a jet engine now. Maybe it wasnt the n249 afterall.
 
Golf, have you got a pic of the reversed N75 valve? I'm up for trying anything if it may have a slight effect on the boost. I've noticed that my turbo is a lot louder since I had a service done 4 weeks ago too!
 
Westle said:
Golf, have you got a pic of the reversed N75 valve? I'm up for trying anything if it may have a slight effect on the boost. I've noticed that my turbo is a lot louder since I had a service done 4 weeks ago too!
Click to expand...

Louder? In a bad way or good way?

G
 
Hmmm...

You sure its not a sign its wearing?

Not to frighten you but doesn't that strike you as odd?

It would me.

G
 
My theory is that the previous owner did his own service and only changed the oil, oil filer and plugs. I know that the oil that went in this time was a better grade and also I thought I might be getting some more turbo noise in the cabin as I have clean pollen filters now!
 
I thought the louder turbo was because of the extra boost from the remap ? Mine just sounds like the turbine blades are spinning faster.
 
Last edited:
Its likely to be louder because it recieve more air flow to it, boosting harder.

Changing the filter, TIP, N75, Exhaust system, smoothed air box or remap will all help with extra / easier air flow to the turbo giving you more boost and noise.
 
Last edited:
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