17705 - Pressure Drop between Turbo and Throttle Valve

[PeteG]

Right. I was driving on a dual carriageway last night, went to accelerate, and at about 2200rpm, the car judders like mad and starts slowing, and the engine management light started flashing.

I read the codes, got - "17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

P1297 - 35-10 - - - Intermittent".

I know it's a fairly common code to have come up, so I did a quick road test today. 1st gear, it pulls through with no judders. 2nd, get to 2200rpm-ish, and it does it again - judders and loses power.

I'm going to try cleaning up the throttle body, but should I be looking for a split hose? The pipe from exhaust to the dump valve, about an inch diameter, has a small slice in it, but not right the way through - could this be making it collapse under load, perhaps?

Where else should I be looking in the engine bay?

[Bowders1]

A throttle clean is a good start.

I am not 100% but also think this may be linked to the standard DV failing

Edited 25 January, 2010 by Bowders1

[vrsjaw]

i had same prob and it was the vac pipe that goes in bitween the injection manifold and head and the pipe that runs near the dip stick...

[Bowders1]

i had same prob and it was the vac pipe that goes in bitween the injection manifold and head and the pipe that runs near the dip stick...

Agree too that hose can split and bring up a number of fault codes but don't recall it causing fault code 17705.

You can also hear a hiss from that pipe if split which is under the front plastic trim before the inlet manifold

[PeteG]

Cheers chaps. Going out to grab some cleaner now.

Couldn't hear any hissing from any pipes, when revved or idling...

[Jigger72]

New N75 valve fixed mine

That was after new DV, checking all hoses, and a throttle body clean didn't fix it

[VRS Nick]

use the search button pal and you will find my thread how i cured my problem

[davojuri]

Right. I was driving on a dual carriageway last night, went to accelerate, and at about 2200rpm, the car judders like mad and starts slowing, and the engine management light started flashing.

I read the codes, got - "17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

P1297 - 35-10 - - - Intermittent".

I know it's a fairly common code to have come up, so I did a quick road test today. 1st gear, it pulls through with no judders. 2nd, get to 2200rpm-ish, and it does it again - judders and loses power.

I'm going to try cleaning up the throttle body, but should I be looking for a split hose? The pipe from exhaust to the dump valve, about an inch diameter, has a small slice in it, but not right the way through - could this be making it collapse under load, perhaps?

Where else should I be looking in the engine bay?

Hi do u use N75 race valve??

I had the same problem. And I changed all the

hoses until throttle body, cleaned it to.

but it was the N75 that is "T"shaped that was wrongly inserted when replaced the OE ones.

Check that please espetialy if you have changed it or if you have changed TIP and they putted it into it in wrong manner.

regards

Davor

[Gonzaga]

You should log your MAF sensor, requested and actual boost, N75 valve and O2 sensor and post it here.

I had this error couple month ago, after replacing the rubber hose between turbo and pancake pipe it went away but now is back.

I did the pressure test and there is no leak in pressure side or vacuum side. What I found out is that this error only occurs when I start the engine in the morning when it is cold, engine starts to shake like it`s running on 2 cyl but after 30 sec everything is OK. (I erase the error everytime)

I have talk to skoda mechanic and he said this could be the MAF sensor or lambda sensor cousing this.

I logged group 002 and in the second gear at full boost air flow is only 130g/s, it should be at least 144g/s. (Air flow= 0.8 x your bhp)

I have changed;

Spark plugs, coils,camshaft sensor G40, timing belt, water pump, turbo hose,oil, filter, DV etc...

I have ordered a new MAF so if this fixes my problem I will post here.

Best regards

Edited 26 January, 2010 by Gonzaga

[vrsjaw]

my light came on again to day with code 17705 and 17704................am sick as i took it to awesome gti and cost me 326...and its back...

[Delcac]

What you need is a new 2L engine and GT30 turbo. Funnily enough I have these for sale.

[VRS Nick]

my light came on again to day with code 17705 and 17704................am sick as i took it to awesome gti and cost me 326...and its back...

what work did you have done for that price ? why not try a skoda dealership they will get it sorted for you . im guess your problem will be a new throttle body if you checked all the pipes .

[vrsjaw]

vrsnick////

the uprated claw pipe ..dip stick pipe a new temp switch...a vag check and 3 hours labour ..when he was only at my car for a hour and half.......lol..am thinking abut buying a new throttle body. how much can you get them for....cheers

[Guest westallc]

throttle bodys from skoda are upwards of £300

nick was lucky i had one for sale

Edited 27 January, 2010 by westallc

[PeteG]

Update on this - I'm trying with the most basic things first... throttle body clean and reassemble made no difference.

I've traced the turbo pipes around the engine, and found the rubber pipe between turbo and pancake was a slack fit. New clip + jubilee clip to hold it tighter, and it seems to feel better, but it is still losing boost in 2nd gear and above. Next step I think is to do a proper fix, with a reducer pipe, to replace the utterly crap fitting on that pipe.

How do I find the logs for the "MAF sensor, requested and actual boost, N75 valve and O2 sensor"? I'm guessing plug the car into my laptop, run VAG-Scope, and take it for a drive?

[Gonzaga]

Yes, you need laptop, vag-com and cable.

Some test are done while driving.

Boost Pressure: MB 115

-For boost, you should note the actual pressure with the engine off. This would be the atmospheric pressure.

If you are near sea level, then you can use 1000mbar as an approximate atmospheric pressure.

-Boost Pressure (actual) is the pressure actually seen by the MAP sensor. You should never see a value below

atmospheric pressure since the MAP sensor is located upstream of the throttle body on the 1.8T engine.

-Boost Pressure (specified) is what the engine requests and you will see vacuum pressure for specified boost.

-Sometimes, it is useful to log both values.

Fuel Trims: MB 032

-These values can be checked with the engine off.

-Generally speaking, you’d want to be within ±10% if you’re stock. If you’re modded, then the mods might have some

affect on the fuel trims. If your fuel trims are way out of whack then you might get a DTC and/or a CEL.

-You can read more about fuel trims here:

http://wiki.ross-tech.com/index.php/Fuel_Trim_Info

Wastegate (N75) Duty Cycle: MB 118

Mass Air Flow: MB 002

-This is the amount of air that’s coming into the engine. Please note that changing the cross-sectional area of the MAF

housing at the MAF sensor will affect the MAF reading. It is not recommended to change the cross-sectional area unless

you have programming to compensate for it.

Intake Air Temperature (IAT): MB 118

-Self explanatory. It is a good idea to log before and after an aftermarket FMIC install.

Air/Fuel Ratio: MB 031

The 1.8T has a wideband o2 sensor which reads in lambda. Only the front o2 sensor is pertinent in tuning, the rear is for

emissions purposes only. Multiply the lambda value by 14.7 to get the Air/Fuel Ratio.

Most logs should be done in a third gear Wide-Open Throttle (WOT) from 2000-6500 rpm. If this cannot be achieved,

then a second gear WOT can be done.

Best regards

Edited 28 January, 2010 by Gonzaga

[karlbar2k]

I replaced a fair bit chasing that code

[VRS Nick]

the uprated claw pipe ..dip stick pipe a new temp switch...a vag check and 3 hours labour ..when he was only at my car for a hour and half.......lol..am thinking abut buying a new throttle body. how much can you get them for....cheers

thats alot of money just to have what youve done i think .

last year skoda wanted £240 for a throttle body . I not to sure if that was fitted tho . it only takes half hour tops to fit anyway but you need someone with a VAG.com to set it up .

there was one on sale on e-bay not long back BUT you are taking a chance because they too could have the same problem as yours , i was very lucky that westallc had one for sale .

[DizMeisTa]

man awesome are expensive! not surprising the amount of staff and size of building they have... rates and wages cost a fortune!

[vrsjaw]

i no ....nice people to deal with but am gunner sort the car out my self even if i need to buy a throttle body......this code is up setting alot of people

[PeteG]

This car is making a fool out of me... fixed the boost pipe, read the codes - no.4 coil pack decided to give up at the same time, so back to the parts shop tomorrow... perfect comic timing.

[karlbar2k]

Its all part of the FUN of driving a VAG 1.8T :D Every day you wonder what piece of crappy pipe is going to split next?

[PeteG]

Haha, too true. One spring clip, one jubilee clip to fix the boost pipe, and two coil packs later... it's fixed! For now at least...

[karlbar2k]

on mine even after fitting a new pipe and clips (the one at back of the block) I still ended up modding the old one instead.

[PeteG]

That's the plan, when I've got some more time off work