2.0tdi 140bhp Engine overboosting

BarnyBarnett

Active Member
Nov 2, 2014
9
0
It's happened twice now, but upon driving home long distance along the motorway, iv had the car lose all power. Upon resetting the car I managed to drive it home and it felt completely normal.

I plugged my OBDII scanner in and it told me the engine was overboosting and gave me the P0234 code.

Upon giving it tame revs, iv noticed a very slight 'tss' sound as the revs drop. Iv only had the car a month so I don't know weather it's a normal sound.

Iv also noticed recently that it doesn't feel as powerfull as it did when I bought it a month ago.

Much appreciated in advanced for any help.
 

BarnyBarnett

Active Member
Nov 2, 2014
9
0
I bought it from a trade seller so I never got a warranty from him.

Iv read it could be a vacuum hose, the pressure boost valve or even a egr hose.

Would it be a case of a new turbo or could I get it cleaned out?
 

Marshall

Active Member
Jul 7, 2008
3,258
5
Bonnie Scotland
If its sticking g vanes on the turbo and you I tend keeping the car then a replacement turbo is the only long term fix.
People try cleaning them with various things like oven cleaner etc but it may free the vanes but can and usually does cause other problems further down the line.
 

seventen710

Active Member
Jul 18, 2012
105
5
Emsworth, Hampshire
Exactly what happened on my PD140, and same error code. Needed new turbo. Local independent VAG specialist says they all go between 60k and 80k miles.

New turbo and fitting cost me £1250 :(
 
Nov 11, 2013
1,263
0
Kent
I'm not entirely sure but I think under the sale of goods act when selling a used car from a business there should be a 3 month grace period which acts as the warranty. I would look into this first as the car isn't fit for purpose so you would be entitled to get it returned or repaired. Easier said than done i know. Research it and see what you find. If all else fails just contact the seller and see what they say. Don't ask dont get
 

GrahamFR

Now AMG Powered
Dec 10, 2008
4,239
5
Barnsley or Burton
mate of mine bought an a4 that had a fault something to do with flaps and the intake but i digress, he scanned it and it showed the fault was there before he bought it so he took it back to the place he bought it and demanded they fixed it and low and behold they did... dont know if this fault comes up on vcds mind...
 

BarnyBarnett

Active Member
Nov 2, 2014
9
0
Thanks for your help guys,
I had the test done on the turbo and it showed that it was over boosting 1st, 2nd, 4th, 5th and 6th. 3rd was underboosting.
I had bought the car from a trade seller therefore I don't think a warranty is in force. Plus I traveled 300 miles to pick it up.
I have been quoted £970 Inc vat and fitting for a OM seat turbo.

But I also have a further question.. Would it be worth looking into a hybrid stage 2 turbo? Iv heard 230bhp stock. But iv not heard anything regarding reliability?
 
Nov 11, 2013
1,263
0
Kent
Has anyone actually confirmed the turbo needs replacing and that there's not another issue causing the over boost. If i had to get new one i would consider a darkside development turbo kit which comes with upgraded turbo, exhaust manifold etc and fitting with custom remap all included. I would imagine that it will eradicate any of the existing problems as it rebuilt to withstand higher tolerances
 
Last edited:

burrell

Active Member
Nov 27, 2009
95
0
Falkirk
I'm sure a failed N75 valve could cause this problem. And that's a simple cheap fix. I'd be trying that first as I'm pretty sure there isn't a code which actually tells you the actuator has failed.
 

eoink

Active Member
Jul 8, 2013
22
0
Ireland
Some useful info on your rights, even to a trade seller.

tradingstandards.gov.uk/cgi-bin/glos/con1item.cgi?file=*ADV0003-1011.txt
 
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