6/8/2014 · What TDI Do I Have – Jetta & Golfs. MkVI, Mark 4, A4, Mk6, NMS.ALH, BEW, BHW, CJAA – The many VW engine and model codes can be confusing. In this article we’ll help you sort through it and determine which model you have. You’ll hear VWs referred to by chassis (A1, A3, B4, etc.). This code refers to both the size of the platform, with