Might be an OBDI vs OBDII problem. I bought a set of oe clears from a guy with 95 M3 (obdI), and they set off codes galore on my 98 328i. I ended up switching back to ambers for a while, before putting on another set of clears.
Folks on this forum suggested the reason for this was the OBDI-v-II. I still have the oe clear tails, figured how could the seller have known...
98 328i, black/black, manual, canadian sport pkg, ECIS intake, koni sport adj's, dinan springs, oe/oem clears.
Considering: tms shark,M 17" wheels, larger sway bars.