P1557 Fault Code Waste Gate Valve Over Pressure

[richfng]

Having serious loss of power issues with my 99 A4 Quattro 1.8 135K miles. During a trip this weekend noticed I lost a lot of power, car takes forever to get up to speed and won't go above 60.... Getting a CEL code P1557 which is an over pressure of the Waste gate control valve..... any idea on how to check this??? Is it just the valve or it is Turbo issues?

Thanks to all in advance for helping out this Newbie

[richfng]

P1557 Turbocharger Boost Pressure Control Valve: Positive Deviation