BMW key programming is often misunderstood. You cannot program a used BMW key fob to start another BMW. This is because the Engine Immobilizer System (EWS) encryption is specific to the Vehicle Identification Number (VIN). The encrypted Individual Serial Number (ISN) is stored in a database accessible only by BMW. New keys must be ordered from a BMW dealership’s parts department after providing proof of ownership and VIN. The key is then shipped to the dealership for the owner.
The central locking system (FZV) and the anti-theft alarm siren system (DWA) operate independently from the EWS immobilizer system. On some older BMW models (E series), a used or another remote can be programmed to lock/unlock doors and arm/disarm the alarm, provided they operate on the same radio frequency (315 MHz in North America, 433 MHz in Europe). However, this key still won’t start the car.
The EWS transponder chip in the key is write-once. Even with aftermarket software/hardware capable of retrieving the ISN from the DME (Digital Motor Electronics) and EWS control modules, you would need to write that data to a new EWS transponder. In older E series keys, the EWS transponder is soldered to the internal circuit board.
Therefore, programming a BMW key to start the car requires a new key ordered and programmed through an authorized BMW dealership. While some functions like locking and unlocking can sometimes be programmed with used keys on older models, starting the engine always necessitates a new, dealer-programmed key due to the VIN-specific EWS encryption.
