See also:

Sound output
Switching on/off When the ignition is switched off: press ON/OFF button on the radio. Muting When the ignition is switched on or the engine is running: press the ON/OFF button on the radio. ...

Safety switch for the rear
Press the button on the driver's door if children are being transported in the rear. This locks various functions so that they cannot be operated from the rear: safety switch. ...

Note
Children in the vehicle Do not leave children unattended in the vehicle; otherwise, they could endanger themselves and other persons, e.g., by opening the doors.◀ ...