P17964 = Faulty Turbo?

[jgoodman00]

Lately my 2001 (130hp) passat has been going into limp mode and shutting the turbo down. No engine management lights are coming on. It has 182k miles on the clock.

I took it into vw who carried out a 'guided fault finding and diagnostic test plan' and concluded the turbo was faulty. The also noted faults were being stored, but didnt confirm what. They quoted a huge £1300 to replace the turbo!

To get a second opinion I took it to my local independent who confirmed the fault codes as P17964 (turbocharger pressure not reached). They could find nothing else wrong and said it was more likely to be a sensor as opposed to the turbo.

The turbo works most of the time, although I am sure low rpm response is much poorer than it used to be. It is also quite laggy. It tends to go into limp mode when accelerating in 5th or 6th gear when the engine speed reaches 2400rpm. It then cuts the turbo completely, and the only way to get the turbo back is to restart the engine. It seems worse when the engine is cold.

So, does it sound like vw are correct and I need a new turbo, or is it likely to be a sensor?
Has anybody else experienced something similar; what did it turn out to be?

Thanks,

[martin1810]

A low pressure fault code is rarely due to a faulty turbo. You should start by changing all the vacuum pipes. That's the cheapest and easiest place to begin.

[Crasher]

Check the ridged vacuum line that runs along the right inner wing where it passes through a metal clip on the air cleaner, it often rubs through. As Martin says, this will be a vacuum leak. If you disconnect the small vacuum pipe from the servo pipe and suck on it, you should not be able to draw air. Another favourite place for rubbing though is right down the back on the left side of the engine bay near the EGR solenoid, the plastic pipe rubs through here as well.

[passat 130 tdi]

goodluck with this as i just spent close to £200 rectifying mine for this problem of turbo shutting down ,mine was code 17965 overboost pressure - turned out to be the thrust sensor in the intercooler pipe at fault . was told vanes were sticking in turbo - quoted £850 by audi/vw specialists.for new turbo+fitting


inspect and separate every vaccuum pipe 1 by 1 so you can reassemble , cover 1 end and blow down the other ,use a small air pump if need be.

[craig.scoobsvil]

My 2002 Bora TDi PD 130 is doing a similar thing. This might drag on but please, bear with me!!!!

It went lifeless on me last week without warning. Re starting the engine cleared it and I drove 40 minutes home without further problems. The next day it did it again so I got the codes checked on a Snap On machine and although the guy cleared the code before I could take note of it he said it was something like Turbo maximum pressure limit exceeded. After much searching and advice I removed the turbo and cleaned it thoroughly and replaced it only to find it was no different. At this point restarting no longer returned my power. I have since replaced the AMM with a new Bosch unit (£93 exchange) and still the problem persists. Since I have owned the car (2 years) I have had repeated trouble with turbo pipes blowing off at the intercooler as mine has the ASZ engine with the silly aluminium push and clip fittings rather than rubber hoses and 'normal' jubilee type clips. I have since replaced some of the hoses and clips which then highlighted a leak on the intercooler which was slightly damaged in a small accident on snow at Xmas and duly repaired where the top mounting brackets had been ripped out. This was just in front of the MAP/IAT sensor. The strange thing about this is although for almost 2 years I have had a number of boost leaks there have been no other boost related issues. Just over 2 weeks ago I finally repaired the leaking intercooler and no longer have any boost leaks. My boost problems started a week after sorting the leak out. I took the car to VW today and no fault codes were present which led them to tell me the turbo must be knackered. I have been in the car tonight and the boost was there although more laggy than normal it was flying for about 5 minutes then dropped off again. Also if I give it loads of revs in 1st, with not a hint of boost, I will get boost in second but not until around 4000rpm. 3rd, 4th 5th 6th will all give good boost if I keep going fast enough to keep it spooled up. Can anyone please shed some light on this as I can't help feeling my problem is something other than the turbo or am I just in denial of the inevitable?

Can I just add that I repaired the intercooler because I cannot find one at a price I can afford. If you have on at a reasonable price please let me know. Thanks

[passat 130 tdi]

My 2002 Bora TDi PD 130 is doing a similar thing. This might drag on but please, bear with me!!!!

It went lifeless on me last week without warning. Re starting the engine cleared it and I drove 40 minutes home without further problems. The next day it did it again so I got the codes checked on a Snap On machine and although the guy cleared the code before I could take note of it he said it was something like Turbo maximum pressure limit exceeded. After much searching and advice I removed the turbo and cleaned it thoroughly and replaced it only to find it was no different. At this point restarting no longer returned my power. I have since replaced the AMM with a new Bosch unit (£93 exchange) and still the problem persists. Since I have owned the car (2 years) I have had repeated trouble with turbo pipes blowing off at the intercooler as mine has the ASZ engine with the silly aluminium push and clip fittings rather than rubber hoses and 'normal' jubilee type clips. I have since replaced some of the hoses and clips which then highlighted a leak on the intercooler which was slightly damaged in a small accident on snow at Xmas and duly repaired where the top mounting brackets had been ripped out. This was just in front of the MAP/IAT sensor. The strange thing about this is although for almost 2 years I have had a number of boost leaks there have been no other boost related issues. Just over 2 weeks ago I finally repaired the leaking intercooler and no longer have any boost leaks. My boost problems started a week after sorting the leak out. I took the car to VW today and no fault codes were present which led them to tell me the turbo must be knackered. I have been in the car tonight and the boost was there although more laggy than normal it was flying for about 5 minutes then dropped off again. Also if I give it loads of revs in 1st, with not a hint of boost, I will get boost in second but not until around 4000rpm. 3rd, 4th 5th 6th will all give good boost if I keep going fast enough to keep it spooled up. Can anyone please shed some light on this as I can't help feeling my problem is something other than the turbo or am I just in denial of the inevitable?

Can I just add that I repaired the intercooler because I cannot find one at a price I can afford. If you have on at a reasonable price please let me know. Thanks

you could try changing the n75 valve.

[craig.scoobsvil]

I'm gonna rip all the pipes off it today and check for blockages/leaks and I'll get the N75 whilst I'm at it. Someone who works at my local Smith Knight Fay VW as a mechanic did let me try an N75 but where mine has the 3 pipes facing the same way the one he loaned me had 2 one way and 1 the other so the vac pipes were a bit stretched. It was a used unit too but either way it didn't make a difference.

[Crasher]

99% of the time it is sticking vanes, a sticking thrust sensor is quite rare but very easy to detect if you know what you are looking for.

I have never seen 17965 from leaking or blocked vacuum pipes, that normally gives 17964.

[passat 130 tdi]

Sticky vanes was my first port of call I got the innotec treatment and used it first code I had did point to split pipe and vacuum loss on the testers computer program though some codes do relate to several possibles and are not conclusive

[craig.scoobsvil]

99% of the time it is sticking vanes, a sticking thrust sensor is quite rare but very easy to detect if you know what you are looking for.

I have never seen 17965 from leaking or blocked vacuum pipes, that normally gives 17964.

The turbo is clean inside. It was removed last Sunday and cleaned out thoroughly. Could a faulty turbo give a 17965 or would it normally be a low pressure reading?