Engine Control Modules Flash (EEPROM) Programming

At the end of 1995 new variations of DME/ECM control modules were introduced that no longer contained a removable EPROM but instead contained a soldered in EEPROM. An EEPROM is an E  lectrically E  rasable P  rogrammable R  ead O  nly M  emory device, which means that programs & data stored on the chip can be electrically erased and replaced with new/revised programs or data. In order to erase the data on the chip a short duration low level voltage/charge is applied to a pin on the EEPROM and the stored data is erased, hence the name "Flash". Once the data is erased new data is loaded.

By using a newer technology, these control modules have the ability to be updated a total of 13 times before they need to be replaced.

Theoretically an EEPROM can be erased and reprogrammed more than 13 times, BMW set the number to 13, since a point will be reached where the update being installed may no longer be compatible with the hardware of the installed module which could result in erroneous operation. If the program is not compatible with the hardware version of the module, the program used to determine the correct update for the module will indicate that the module will need to be replaced before the update can be performed.

The reference to Flash programming is a result of the technology used to erase the EEPROM prior to installing a new program and or data.

The control modules listed identify when EEPROMs were first introduced into the DME/ECM:

The utilization of EEPROMs within the Engine Management Systems continues to be used today, and has expanded into other control modules as well.