Storage of Programming Data

In it's unprogrammed basic state, the EPROM only contains "resident data". The resident data provides control module/ EPROM identification to the programming software prior to programming.

Fig 1: Identifying EPROM Control Module (Basic State)

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Identifying EPROM Control Module (Programmed)

Courtesy of BMW OF NORTH AMERICA, INC.

When programmed, the EPROM is filled with the required characteristic maps (ignition timing, injection etc), control module constants, Identification data, etc.

When is programming necessary? 

Programming an engine control module is necessary when:

• Installing a replacement basic control module
• Recall or Service Action campaign: This falls into one of the following catagories:
  • Program update to existing program
  • Complete programming procedure after EPROM replacement.