Is the SD card in place? Did it quit working suddenly? The head unit will not function without the correct SD card for the car so you may need to purchase a new SD card programmed for the car through Nissan.
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015