Programming a new key for a 2009 BMW 730Li (F02 chassis with CAS4 system) involves clear choices. While OBD key adding is faster, bench reading the CAS4 module avoids potential module bricking during memory extraction.
Here is the verified process using KEYDIY KD–X4 and KD–EPA Adapter.
Required Tools
- KD-X4 Key Programmer
- KD-EPA Programming Adapter
- KEYDIY KD FGB23 Key
- OTG Cable
- Soldering tools and wiring harness
Note: For BMW CAS module decryption, need to activate with 2000 K-coins.
Step 1: Vehicle Prep and CAS4 Removal
Disconnect the negative battery terminal to protect the vehicle electronics.
Remove the lower dashboard trim panel on the driver side.
Remove the mounting screws securing the CAS4 anti-theft box.
Unplug the 3 main connectors and pull out the CAS4 module.
Step 2: EEPROM Data Backup
Open KD–X4 app: Immo Programming> KD-X4/KD prog mini> Read file> IMMO> BMW > CAS4–1L15Y [Backup Read]> EEPROM
Check the built-in wiring diagram in the app and solder the harness wires to the designated board points.
Connect KEYDIY KD–EPA Adapter and OTG cable to KD–X4 key programmer.
Read and save the EEPROM file. (We recommend reading and saving the D-FLASH/Preflash file as a backup).
Files are stored locally in File Management > Local File under today’s date folder.
Step 3: Module Reinstallation
Reinstall the CAS4 box back into the car, reconnect the 3 harness plugs, and tighten all screws.
Reinstall the trim panel and reconnect the battery negative terminal.
Step 4: Writing the New Key
Connect KD–X4 OBD cable to the car’s OBD-II port.
Select IMMO Programming > immo Programming> BMW > Select by Type> CAS4/CAS4+ > Start execution> 1L15Y Type
Confirm the vehicle VIN on the screen.
Select Load from Local File and load the EEPROM file saved in Step 2.
Choose an open key slot (e.g., Key 3).
Place the new blank KEYDIY KD FGB key into the key slot of KEYDIY KD–X4 programmer, select KD–FGB remote, and click Generate Common Dealer Keys to complete writing process
Step 5: Testing
Hold the new key against the key marked sensing area on the right side of the steering column.
Press the Start Button to start the engine.
Turn off the engine and test the remote lock/unlock buttons to confirm full operation.
