Boost issue

Redworminator

Active Member
Sep 4, 2019
47
13
Have a little issue with my 2001 LC, when I first start it up for the day I seem to have no boost, it drives like a 1.8 n/a. If I turn it off and back on, it drives absolutely fine for the rest of the day regardless of how many times I turn it off and back on again.
I replaced the DV with the latest OEM one from Seat, no change. I unplugged the MAF but no change, then I replaced the N75 with a like for like, now there is no boost at any time and throws up code 17705, I put the old one back on and once I turn it off and back on drives fine, I can live with this but would be nice to be able to get to the bottom of it, anyone have any ideas?
 

Andrewwright

Turbo lover
Aug 16, 2016
1,568
224
Peterborough
Have a little issue with my 2001 LC, when I first start it up for the day I seem to have no boost, it drives like a 1.8 n/a. If I turn it off and back on, it drives absolutely fine for the rest of the day regardless of how many times I turn it off and back on again.
I replaced the DV with the latest OEM one from Seat, no change. I unplugged the MAF but no change, then I replaced the N75 with a like for like, now there is no boost at any time and throws up code 17705, I put the old one back on and once I turn it off and back on drives fine, I can live with this but would be nice to be able to get to the bottom of it, anyone have any ideas?
Unplugged the MAF but no change??
MAF is broken.

Sent from my Nexus 6 using Tapatalk
 

Redworminator

Active Member
Sep 4, 2019
47
13
Do you think? even though I could drive it all day ( as I did on Saturday) on the second start up with no issues? What should happen if you unplug a good MAF? Thanks
 

Alexis27

Active Member
Dec 20, 2009
2,095
451
Manchester
N249 valve is one possibility. Although it rarely fails - it's almost always the accompanying pipe work
 
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Redworminator

Active Member
Sep 4, 2019
47
13
Ok I'll get a new MAF and check the pipework, then go from there, I'm a little confused about the N75 though
 

Alexis27

Active Member
Dec 20, 2009
2,095
451
Manchester
What is the code on the new one? And was it a genuine OEM one or a cheap Chinese copy? You can't really get a genuine one for less than £55.
 

Andrewwright

Turbo lover
Aug 16, 2016
1,568
224
Peterborough
Ok I'll get a new MAF and check the pipework, then go from there, I'm a little confused about the N75 though
Before you do that check it again. There £75+ so have it running, pop the bonnet and unplug it. If no change then yes it's faulty. Smoke test will help no end with air leaks.

Sent from my Nexus 6 using Tapatalk
 

mty12345

Active Member
Jun 17, 2011
3,727
451
bristol
Ok great thanks for the advice, I'll give that a go in the morning

I very much doubt it is the MAF or infact anything physically wrong with the car at all.

17705 is a common code caused by a certain parameter that gets over looked when cars are remapped. It usually only shows up in the winter, because it is only triggered when the car is started from 5C or below. When you turn the key off and back on again, the car is now starting from warm so that code won't be triggered again until the next cold start. This is why it only usually does it once a day.

I have some info somewhere on it somewhere. I will find the link for you later when i get chance. Hold off on the MAF for now mate

Edit: here you go buddy. https://18t-tuning.co.uk/17705-pressure-drop-between-turbo-and-throttle-valve/
 
Last edited:
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mty12345

Active Member
Jun 17, 2011
3,727
451
bristol
Yep, when i first got mine that code drove me crazy for months. If you want to sort it then see if you can find a mapper willing to change the value of the parameter called 'FVPDKLDUS' from whatever the current value is to a '0' instead.

I've been on here 8 years and problems with this code come up every time the weather gets cold.
 

Redworminator

Active Member
Sep 4, 2019
47
13
Thanks mate, I don't think I'll bother doing anything I can live with it. And I'd probably guess that the N75 I bought is faulty, I'll just get another or a refund.
 
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Redworminator

Active Member
Sep 4, 2019
47
13
Well not in my ownership or any receipts from previous owner, but I had it rolling roaded last week and is putting out 188bhp 237lb/ft so thinking yes probably
 

Alexis27

Active Member
Dec 20, 2009
2,095
451
Manchester
Ah, yes the remap that isn't making as much power as it should! Crappy map could be something to do with your fault code
 

Redworminator

Active Member
Sep 4, 2019
47
13
Yeah possibly, I'm happy with how it runs tbh, I'll run it into the ground then get myself a R, it only cost me £700 so wouldn't make sense to spend £400 on a remap to me.
 
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