This bulletin applies to 2013-2014 Audi A4, A5, A5 Cabriolet, A6, Q5 and TT vehicles equipped with a 2.0L engine. The MIL may be on, and reduction of power may be experienced and DTC P029900 (turbo/super charger underboost) may be stored in the ECM. The circlip connecting the turbo wastegate actuator rod and the wastegate flap lever can fall off due to low clip tension. An improved replacement clip is available that provides higher tension.