SYSTEM AND METHOD FOR DETERMINING TURBINE DEGRADATION AND MITIGATING TURBINE DEGRADATION IN A VARIABLE GEOMETRY TURBOCHARGER

A method for operating a vehicle system is described herein. The method includes indicating a variable geometry turbine degradation based on a comparison of a modeled set of turbine pressure values and a sensed set of turbine pressure values, each set of turbine pressure values including a pressure value upstream of the turbine and a pressure value downstream of the turbine and the variable geometry turbine positioned downstream of an engine cylinder.