Check the 12 volt battery voltage at rest. If you are lucky, the car just has a low or failing accessory battery that may need to be charged or replaced. If the battery reads 12.5 volts or higher, that isn't the problem, although it should be charged up if reading 12.3-12.5. Below about 12.3 volts and that may be the only problem. The Leaf doesn't always keep that battery charged properly, so if it's low, invest in a little battery maintainer, and use it at least twice a month.
Personally I wouldn't buy a car that was throwing a code that was simply reset. They do have a way of coming back!
2013 "Brilliant Silver" SV with Premium and no QC, a 2009 Vectrix VX-1 W/18 Leaf modules, and 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.