Since the advent of the E46 and the late E39, the BMW key itself serves as a memory chip as well as an immobilizer. In general, the immobilizer has two or three hex codes in the key, and most of the companies have further programmed with VIN. BMW key itself is GSM It is used as a SIM (Subscriber Identification Module) card used in mobile phones.
Various information is stored in the key as well as the immobilizer. In simple terms, it is not only the time for replacing the engine oil and configuration of the chairs and radio and memory, but also stored the snapshot information by OBD-II and all the information received from the ECU at the time the warning light was generated.