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P0299 ( Turbocharger underboost) problems

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September 8, 2025Sep 8

Hello everyone, I drive an a4 b8.5 2.0 tdi quattro and I’m currently getting the code p0299( turbocharger underboost) when going above the speed of 50 mph and it puts me in limp mode. I’ve checked hoses for any cracks or leaks but cannot see any, my first bet was to try and either the replace the n57 valve or the actuator. Has anyone had any similar problems before I go into start replacing parts and hoping for a fix?

thank you for reading 😀

2 months later...

November 24, 2025Nov 24

Did you fix this?

I had the same issue and it was my brake booster. Smoke tester will find vac leaks fast.

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Are S5's notorious for not being serviced?

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P0299 ( Turbocharger underboost) problems

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Topics

Are S5's notorious for not being serviced?

C5 RS6 034 strut top mount

Help with some issues

Wing mirrors don't fold out when unlocking the car.

Park My A3 without having brakes on

A3 uncommanded engine shutdown

Audi A1 coil packs

Central locking

GEARBOX MALFUNCTION YOU CAN CONTINUE DRIVING

A% front suspension groan

Any ideas on what this sound could be? Audi A3 8P

Does anyone know what this high pitched noise is?

Alternator failure related to mild hybrid system?

A6 2018 C8 3.0tdi quattro drivers mirror indicator

S-Line suspension change

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