park assist Citroen DS3 2009.5 1.G Owner's Manual

Programming Operating faults
If there is an operating fault, when reverse gear is engaged this warning lamp comes on on the instrument panel, accompanied by an audible signal (shor t beep) and a message on the multifunction screen.
You can activate or deactivate the system by means of the multifunction screen configuration menu. The system state is memorised when switching off the ignition. For more information on access to the parking assistance menu, refer to vehicle configuration in the "Multifunction screens" section corresponding to your screen.
The system will be deactivated automatically when towing a trailer or when a bicycle carrier is fitted (vehicle fitted with a towbar or bicycle carrier recommended by CITROËN).
In bad or wintry weather, ensure that the sensors are not covered with mud, frost or snow.