M3.1 Engine Control Modules
Beginning with M3.1 DME/ECM control modules, BMW introduced the ability to program an EPROM using BMW diagnostic equipment. On the M3.1 control module the originally installed EPROM needs to be removed from the control module and a new partially blank EPROM installed in order to update the existing control module.
For the M3.1 systems the replacement EPROM that is installed does not contain all the data necessary for the engine to operate, it is a "basic" EPROM that only contains some basic data referred to as "resident data" which helps identify the module and allows the diagnostic equipment to determine what program and associated data needs to be installed/loaded.
