Mercedes-Benz produced the first production car with an integrated keyless entry and ignition system.
The system was called Keyless-Go and appeared on the W220-generation S-Class around 1998. It allowed the driver to keep a coded electronic card or transmitter nearby: the car could recognize it for access, while the engine could be started without inserting a conventional metal ignition key.
The underlying technology was developed by Siemens in the mid-1990s, so Mercedes-Benz did not invent every component from scratch. Its distinction was bringing passive entry and keyless starting together in a production automobile. Some sources date the market introduction to 1998, while Mercedes materials and markets sometimes refer to 1999.
A frequent confusion is between remote keyless entry, which only unlocks doors with a button press, and passive systems such as Keyless-Go, which detect the key automatically and also authorize starting.