If the throttle is closed while the engine is overrunning, back pressure will develop in the compressor housing due to the constant pressurization. This back pressure significantly reduces the speed of the compressor impeller, with the ultimate result of reduced boost pressure and increased turbine lag. To avoid this, the turbocharger shunt air valve is opened by an electric actuator. The valve opens a bypass pipe that allows compressed air to rotate through the compressor blades back to the intake side of the compressor loop. In this way, the required turbine speed is maintained. When the throttle opens, the turbocharger shunt air valve closes and the booster pressure is immediately available. This Part Fits the Following Vehicles Make Model Audi A1 (8X1, 8XK) (2010/05-2018/10) Audi A1 Sportback (8XA, 8XF) (2011/09-2018/10) Seat Alhambra (710, 710) 711) (2010/06 - X) SEAT IBIZA IV ST (6J8, 6P8) (2010/03 - 2016/07) SEAT IBIZA IV (6J5, 6P1) (2008/03 - 2017/12) SEAT IBIZA IV SPORTCOUPE (6J1, 6P5) (2008/06 - 2018/12) SKODA FABIA II (542) (2006/12 - 2014/12) SKODA FABIA II COMBI (545) (2007/10 - 2014/12) VOLKSWAGEN TOURAN (1T1, 1T2) (2003/02 - 2010/05) VOLKSWAGEN POLO (6R1, 6C1) (2009/03 - X) VOLKSWAGEN GOLF VI CONVERTIBLE (517) (2011/03 - 2016/05) VOLKSWAGEN JETTA IV (162, 163, AV3, AV2) (2008/01 - X) VOLKSWAGEN TIGUAN (5N_) (2007/09 - 2018/07) VOLKSWAGEN GOLF V (1K1) (2003/10 - 2009/02) VOLKSWAGEN GOLF PLUS (5M1, 521) (2004/12 - 2013/12) VOLKSWAGEN JETTA III (1K2) (2004/09 - 2013/12) VOLKSWAGEN GOLF V VARIANT (1K5) (2007/01 - 2009/07) VOLKSWAGEN BEETLE (5C1, 5C2) (2011/04 - 2019/07) VOLKSWAGEN SCIROCCO (137, 138) (2008/05 - 2017/11) VOLKSWAGEN GOLF VI (5K1) (2008/10 - 2014/02) VOLKSWAGEN EOS (1F7, 1F8) (2006/03 - 2015/08) VOLKSWAGEN GOLF VI VARIANT (AJ5) (2009/07 - 2014/07) VOLKSWAGEN SHARAN (7N1, 7N2) (2010/05 - X) VOLKSWAGEN TOURAN (1T3) (2010/05 - 2015/05) VOLKSWAGEN BEETLE CONVERTIBLE (5C7, 5C8) (2011/12 - 2019/07) VOLKSWAGEN CC (358) (2011/11 - 2016/12) VOLKSWAGEN PASSAT (362) (2010/08 - 2015/12) VOLKSWAGEN PASSAT VARIANT (365) (2010/08 - 2015/12) VOLKSWAGEN PASSAT (3C2) (2005/03 - 2010/12) VOLKSWAGEN PASSAT VARIANT (3C5) (2005/08 - 2011/11) VOLKSWAGEN PASSAT CC (357) (2008/02 - 2012/01)