Failing accessory batteries, and the phantom major problems they can produce error codes for, are something that we at this forum know more about than most Nissan dealers. Dealership techs are trained to replace the parts indicated as being failing by error codes until the codes are gone. It doesn't matter if the parts are very expensive, or should be producing failure symptoms along with the error code(s) but aren't... I was once quoted $3k for a new transmission on a used Volvo 240, when all it needed was one new solenoid. That repair cost $150 at an independent garage.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.