On some cars that use the CAN bus to communicate between the headunit and the steeringwheel controls, backup cameras etc. that may need to be programmed using a Consult console, but then again, it might just be plug and play.
My experience is with VW/Contential headunits, and it needed to be set up.
Not sure with the Clarion radios. Goggle on installing Clarion Headunit [model number here]
2014 LEAF SV
Delivery May 23 2014
50,000+ miles - all 12 bars - Same range as new - No warranty issues ever!