Cautions in Removing 12V Battery Terminal and AV Control Unit (Models with AV Control Unit)
WARNING: This page is about a different car, the 2011 Nissan Leaf. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Remove 12V battery terminal and AV control unit after a lapse of 30 seconds or more after turning the power switch OFF.
NOTE:
After the power switch is turned OFF, the AV control unit continues operating for approximately 30 seconds. Therefore, data corruption may occur if 12V battery voltage is cut off within 30 seconds.