While idleing I went to engage the triptronic and heard a loud pop, there after my triptronic would not engage but the automatic side still worked, I have had this problem looked at, and it is not a shift cable or selector cable since this component is electronic. to fix this problem you must replace the shift selector column, this can be easly done but is costly, if you buy the parts and fix it your self it is simple to do and the Haynes manual for vw and audi a4 can help you accomplish this. it will take no longer then 4hrs to complete