Steve is correct Randy it's MS43.1, MS45.1(newest version for M54 engines) it has an HFM sensor on the secondary air pump. MS42.2=M52TU(323&325)MS41.1=M52(The first SIEMENS engine managment for 6 cyl) Motronic and Siemens both have VANOS DEPENDING on the engin... Login to read more.