Chip-Tools

ITDEENBGES

BMW CAS4: preparing a key from an XEP100 dump with PCF7939 (working key or DME/DDE ISN)

Procedure for preparing a CAS4 key starting from the EEPROM dump of the XEP100 MCU. The software asks for either the read of a working key or the DME/DDE ISN.

Procedure

1. Read the EEPROM of the CAS4 XEP100 MCU with a programmer and save it to a file.
2. Start the Tag Key Tool with the PROTAG connected and load the file into the software.
3. Select the correct key position where you want to write the new key.
4. Prepare the blank: use a PCF7939 transponder or a new remote key.
5. Place the transponder or key in the correct slot of the PROTAG and start the key preparation.
6. When the software asks, use the corresponding box to choose whether to supply a working key to be read or to enter the DME/DDE ISN, depending on what you have available.
7. Once you have made the choice, press "Prepare Key" to prepare the key ready for programming.
8. Then complete the key programming on the vehicle and check starting and remote functions.

Reference screenshots