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Roman
Roman, Technician
Category: Audi
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Experience:  over 20 years vw audi and porsche technical repair
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Audi: I have 2003 audi a4 1.8t 5 speed. Fault code p0299 turbo

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I have 2003 audi a4 1.8t 5 speed. Fault code p0299 turbo underboost. I have replaced diverter valve and N75 solenoid is "clicking" What could be up here?

Roman :

Hello , Here to answer automotive questions and make you feel comfortable and become familiar with your product

Roman :

the only part left that you did not change is the Faulty charge Air pressure sensor

Roman :

Did you test the MAF ssensor

Roman :

what engine do you have ? did you test the waste gate on the turbo ?

Roman :

16683/P0299/000665 - Boost Pressure Regulation: Control Range Not Reached


Possible Symptoms



  • Reduced Power Output

  • Limp Mode



Possible Causes



  • Hoses/Pipes incorrect connected, disconnected or leaking

  • Charger Pressure Control defective

  • Turbocharger faulty

  • Diverter Valve faulty



Possible Solutions



  • Check Hoses/Pipes to/between Components

  • Check / Clean / Replace Charge Pressure Control

  • Check Turbocharger

  • Check Diverter Valve



Special Notes



  • When found in 2.0l TFSI:

    • Check Boost Pressure Control Valve (N249), for cracked rubber diaphragm. A new/optimized Valve is available under Part # XXXXX (or newer).

      • RoW vehicles see: TPI(NNN) NNN-NNNNfor details.

      • NAR vehicles see: TSB 01-07-70 or(NNN) NNN-NNNNfor details.





  • If the Turbocharger is faulty due to mechanical / internal problems or the exhaust system is restricted (typically the Catalyst) this fault may be the end result.

Customer:

No test on MAF

Customer:

No test on MAF its not in limp mode . its drives good but just not that 1.8t boost it shoul have. dv replace . n75 working I bypassed N249 which many people do to see if its that valve

Roman :

so your saying that it does not have a check engine light on ?

Roman :

check to make sure that the hoses to the turbo condenser are tight and not leaking

Roman :

check the turbo wastegate, it will not throw a code

Roman :

what engine in the car

Customer:

1.8t no leaks

Roman :

then you must test the turbo wastegate. remove the hose from the wastegate and blow shop air into ot and see if it works.

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