Audi 2009 2.0 TDi P0299 fault code saying Turbo charger under boost!! Please help?

[Gorman]

Hi Guys,
Just had P0299 fault code on my 2008 Eos DSG, 80,000 miles keeps going into limp mode, comes out of limp when turned off and restarted but is down on power.
The code is very ambiguous so any help would be gratefully received

[g60dave]

Gorman - how did you get on?

[PetSKi]

CBBB engine on A3 Sportback. First warm day of summer and noticed, the AC was u/s. Have had this emissions ECU recall active and was to get reprogramming scheduled on Tue. Got the blinking glow plug lit on Sun (Engine addjustment failure). Then turned engine off and restarted and it was gone to be blinking again right the next run with continuous Exhaust control failure indicator (Engine icon), which didn't go away. Day before the failure I had driven long run at 130+ km/h and ESP/ASR Off for a couple short runs on gravel.

Took the car to the dealership for the ECU update, but as it is, engine fail active, they couldn't update it. Error code is P0299, continuous underboost. AC was refilled and works now fine, but they couldn't find the actual failure on the engine. Checked the vacuum tubing and the actuator bell, which had been defined to be OK. They said, it could still be the actuator, but didn't have a spare at hand. So they couln't do anything before next morning.

A bit puzzled at the moment hearing controvercy information on how to continue. They figured that culprit might still be a faulty magnetic valve, but wasn't certain on it. That's however, what they would have tried to change, but recommended to schedule new check with electronics specialist. I need the car daily and could not afford it to stay at maintenance overnight.