This guide shows you how to restore the original immobilizer (IMMO) security password on BMW G Series BDC2 modules after an all-keys-lost procedure using Yanhua Mini ACDP/ACDP2 (with Module 38 and AKL bench platform).
After performing all keys lost, the system’s security password changes and the BDC2 becomes locked, then the old key cannot be used, even official dealer keys—will stop working, and you cannot add new keys until the original IMMO data is restored.
Step-by-Step Procedure:
1. Back Up DME EEPROM
Remove the original car engine computer and connect it to Yanhua ACDP via the DME adapter.
Shorten the jumper cap to the CAN-R terminal.
Run Mini ACDP App
Select BMW → DME ISN → Bench Mode Read/Write DME ISN → BOSCH DME → Gxx → B48 ECU (e.g. MG1CS003 SPC5777).
Read and save EEPROM data (file must end with “EEPROM.bin”).
Remember the file path, date, time, and chip model.
2. Identify Vehicle Info
Reinstall the DME, connect it to ACDP2 via OBD
Select FEM/BDC → IMMO/Mileage → BDC2 ICP+OBD (F/G Chassis) → All Key Lost.
Identify vehicle info and then save it. Verify that the IMMO type is supported.
3. Obtain keys data
Remove the BDC2 module and connect via the ACDP Module 38 BDC2 interface board.
Select “Obtain keys data”
Step 1: Read coding data
Save the file ends with “Coding.bin”
Step 2: Read keys data
Read and save key data (file ends with “BdcData.bin”).
Step 3: Write coding data
Upload the saved “Coding.bin” file to write
4. Restore original IMMO data
Reinstall BDC2, connect via OBD, and select “Recover original IMMO (Needs to read DME EEPROM first).”
Perform the 6 steps as follows
Step 1: Backup coding data
Step 2: Backup FAFP data
Step 3: Write IMMO data
Step 4: Write coding data
Step 5: Write DME ISN
Step 6: Reset EGS EWS
Step 1: Backup coding data
Step 2: Backup FAFP data
Step 3: Write IMMO data
Use the BAV-Key Adapter and original dealer key (save files as “BmeEep.bin” and “BmwImmo.bin”)
Step 4: Write coding data
Step 5: Write DME ISN
Unlock DME (the IMMO status is locked)
Select bmweeprom.bin to unlock DME data
Write DME data
The IMMO status is Unlock now
Select “BMWImmo.bin” and check if the IMMO data is correct
Step 6: Reset EGS EWS
The system IMMO status is Unclear
Upload EEPROM data to clear
Finally, go to test if the dealer key or recovered lost key functions properly.
Kindly notice:
After restoring the original immobilizer data with Mini ACDP2—whether using a new key from BMW or a lost key—any key you programmed during the earlier all-keys-lost procedure will no longer work.