Activating/deactivating the hazard warning lights
Press button 
.
. The hazard warning lights will switch on automatically if:
the airbag has been deployed.
the vehicle is heavily braked from a speed of more than 70 km/h to a standstill.
When you pull away again, the hazard warning light system will switch off automatically at approximately 10 km/h. You can also switch off the hazard warning light system using the warning lamp button.