Hi just wondering if anyone could help I was driving my car the other day (audi a3 07 2 litre diesel) and went into limp mode but didn't get no check engine light or anything restarted car and went away but the car feels alot less powerful and also more noisy like air suction nosies  after getting home I plugged in my code reader and it showed a p0299 turbo underboost I've taken it to the garage and they've told me I kneed a new turbo however ime just wondering y is the engine light not coming on do u rekon it does kneed a whole new turbo or couldn't be so thing else don't know if the garage just saying kneeds whole new turbo cus they don't want to mess round with it. 

Adam. On the facts you have presented nobody can possibly tell you what is wrong. It may be a turbo fault, it may be a damaged duct, it may be something else entirely. You or your mechanic need to first of all look for visible damage, and then proceed from there depending on what you find. Error codes can not be relied upon to tell you precisely what is at fault; they can only point you in the general direction.

Hello Adam,

Thanks for being in touch with the forum. 
As I see it, you are questioning your garage’s diagnosis of your issue - and there is nothing wrong with double checking, if you have valid reason to disbelieve such diagnosis. As Cliff says, it would be very difficult for anyone on here to ‘guess’ the possible causes, without access to the car. 
If this were mine, I would not be bothering with ‘normal’ garages, but seeking advice from a recommended, trusted, local diesel specialist. As I keep repeating, to a point of boredom, ask around your local taxi rank for recommendation on local diesel specialists, since taxi owners depend on good service at reasonable rates. 
Perhaps you could let us know how you get on. 
Kind regards,

Gareth.