Method for triggering a command in a motor vehicle by means of a data exchange between a control device and an identifier element

A communication system comprising:

• a communication device which is fitted in a motor vehicle;
• and
• at least one mobile device,
• said communication system being configured to ensure an exchange of data between the communication device and the at least one mobile device,
• the communication device comprising a low-frequency communication interface and a wireless communication interface according to Bluetooth Low Energy (BLE) protocol in an advertising state,
• wherein the communication device communicates with said at least one mobile device, firstly in low-frequency mode and according to the BLE protocol, and secondly according to the BLE protocol alone, and
• wherein after a triggering event, the wireless communication interface according to the BLE protocol switches from the advertising state to a scanning state.