Fault code DTC 00665 turbo under boost ??

[DuBBully]

Took my car to vw for its service and they tell me I have this fault code 00665 turbo under boost coming up, they wanted to charge me £75 to investigate it but I thought I'd ask on here first to see if anyone else has had the problem and how much it cost to sort out.
Any help much appreciated.
Cheers

[bacillus]

If you're prepared to investigate yourself, I would first check that your dv hasn't got a tear.

[Tortaruga]

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 # 06H-145-710-D (or newer).  RoW vehicles see: TPI 2016331 for details.
 NAR vehicles see: TSB 01-07-70 or 2013392 for details.

 When stored in conjunction with misfire codes and/or fuel trim faults see the notes associated with the following faults regarding PCV failure: Crankcase Breather Valve

 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.
 When found in VW Golf/Jetta (1K): 2.0l CR-TDI (CBEA/CJAA):  Verify the mechanical part of the Exhaust Valve Control Module (J883) is not siezed or binding.