17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

Hi.

Im still getting 17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) on my 1.8T AUQ

I have had this on an off since I have owned the Anniversary last year.
In an attempt to cure it I have done the following

Serviced my forge 007p DV (green spring)
Removed PVC system and running an oil catch can.
Replace the TIP with a silicone TIP
Replaced the 5 boost pipes.
and also done a N249 bypass.

All this and today the car went in to limp mode again with the old '17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)'

Has anyone else got an idea to what can be causing this as its driving me mad as I've spent so much already trying to fix it!

Cheers
Dan

 

n75 valve causes this.

 

Really??? I have read and read about this and as you see, slowly changed everything I've been told *could* cause this problem. Is it worth buying a better N75 or stick with an exact replacement?!

 

Exact replacement makes most sense

As said above it is very likely to be at fault causing that fault code

 

I could of saved a lot of cash if I had got this kinda reply last year lol - but on the flip side.. at least I now have a silicone TIP and boost pipes, catch can and n249 delete lol

 

Clean the throttle body, youd be suprised how many times that fault will appear if the TB is gunked up.

Remove the TB, clean it with a rag and brake cleaner or petrol, re-fit it then do a TB alignment

 

TB isnt that bad when I last checked. Is it easy to aline the TB on an AUQ?

 

Ross tech wiki is your friend - http://wiki.ross-tech.com/wiki/index.php/17705/P1297/004759

Advises you of the code, associated symptons and resolves and also how to do the TB alignment

 

I'll double check the TB today before buying a n75.

Sometime on first start up, the secondary air pump kicks in, and if I try to pull away it's very lumpy, almost like its gonna stall, but then goes... Also I get a funny idel, sits at about 850rpm for a couple of seconds then dips slight then back to normal idel.

 

Had this on my cupra,changing a few VAC and breather hoses fixed it,one was the Y shaped pipe you'll of removed for the catch can though (had a big hole in it)
The other was the PCV pipe running to the under side of the inlet manifold.

 

I've replaced all vac hoses now I think ?!? Didn't get to check TB today, I'll look tomorrow.

 

Yep, breather pipes has been the most common fault I've found

 

Took TB off today, wasn't that bad, gave it a good clean, replaced and realigned with Vagcom. Will see how it goes before buying n75.

Is there anyway to test a N75?

 

Whats the outcome of this?

Only real way to test if its the N75 is to find someone with a spare that you know is working 100% and swap them between the 2 cars

 

Well... Cleaned TB and there does seem to be a difference. I've started car in morning and pulled away ASAP and smooth as anything. I'm trying to force the limp mode but failing... Which is good!! Only time will tell. I think I'll hold off getting a n75 valve unless this fault comes back.

 

I had this one my MK4 - AUM 1.8T.

It was exactly the same symtoms and turned out to be part of the PCV system underneath the inlet manifold. One of the pipe had a split in it, and was causing a drop in idle and pulling off it seemed like it wanted to cut out!

I replaced mine with silicone hoses and its been fine ever since

 

Mine was still doing it even after installing silicone, however the cleaning of the TB, so far, seems to have worked :-)

 

I've heard the N75J valve is far better than the older N75 - perhaps it would be worth upgrading for peace of mind?

 

the J just holds boost at first with gives quicker pick up, then its just the same, so I think I may just (if I change it) stick with a like for like replacement.

 

Glad to hear that the TB clean and alignment has brought a little smoother running to your car.

The N75J provides a larger spike on initial spool due to different internals (electrical) which isnt regulated by the ECU, this sometimes will throw the EML light on due to a deviation fault and safety in the software

Hope the TB clean sorts all the problems though