Help urgently required, audi not picking up speed.

Sometimes randomly (like once in a week) my 2004 a3 2.0 TDI S-Tronic doesn't pick up speed at all when I reach roughly around 40mph, the car especially struggles to pick up speed 40+.

I originally thought it was the MAF so I got this replaced however the car still has the problem. I took it to the mechanic where he scanned the car for any errors and showed me the results. The problem is he's not a specialist on diesels and when i identify the problem he will give the car to another specialist mechanic to get it fixed.

I urgently need help from someone who knows what they are talking about to help me identify the problem so my mechanic can tell the specialist to get that error fixed asap. I need to come back to the mechanic on Monday to book an appointment and i have a new job starting Tuesday so urgently need someone's help.

I have uploaded pictures of the errors that came back from the diagnostic test, can someone please help me identify which error listed is due to the car not picking up.

The forum is the best place I thought to get the help.

Regards

Juman.

I spoken with an audi expert and apparently the first error code (code P0234 Boost pressure control above control limit) seems to be the problem. Is there anything I can do from home to get this fixed or would anyone know roughly how much a mechanic would charge me

All the mechanics were telling me to change the turbo due to the noise the turbo was giving out (high pitched noise) but one of my local mechanics said he's dealt with limp modes before and he's gonna try clean the egr valve with some special chemical he's got. That seemed to have worked for like three weeks then the problem slowly began creeping back up but not as bad so atm iv taken it back to the mechanic who will reclean the egr valve again for free. Iv got a feeling it's the n75 valve therefore does anyone know where I can pick that valve up or post a link on this thread to it please?

@udi A3 said:

[h=3]16618/P0234/000564 - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)[/h] [h=4]Possible Symptoms[/h]

• Malfunction Indicator Light (MIL) ON
• Boost Pressure too high
• Reduced Power Output

[h=4]Possible Causes[/h]

• Hoses incorrectly connected, disconnected, blocked or leaking
• Boost Pressure Control Valve (N75) faulty
• Boost Pressure Sensor (G31) faulty
• Turbo Charger stuck/faulty

[h=4]Possible Solutions[/h]

• Check Charge Pressure Control System
  • Perform Output Test (to check the Turbo Charger)
  • Perform Basic Setting (to check the Charge Pressure Control)
  • Perform Pressure Test to locate Leaks
• Check/Replace Boost Pressure Control Valve (N75)
• Check/Replace Boost Pressure Sensor (G31)
• Check/Replace Turbo Charger

Click to expand...

The leaking hoses being talked about on this post, are they connected to the N75 valve?

I have found a replacement part and was wondering if the hoses included are the leaking hoses being mentioned on the post above:
http://www.europaparts.com/n75-valve-06f906283f.html

I'd rather give this a try then dish out £700+ for a new turbo