When a specific pressure is exceeded the pressure regulating valve allows fuel to escape from the high pressure fuel rail. If the pressure release valve has gone bad, then it can cause low fuel rail pressure which results in fault codes, lose of power, and a high risk of melting a piston within the engine . This Part is a great upgrade from your stock 2.0T pressure regulator valve which has an opening pressure of 130bar. With an opening pressure of 165bar you will be able to delivery more fuel to your 2.0T FSI engine giving the ability to make more horsepower.
This is for big turbo applications mostly!