ype, I picked up a used 2015 Nissan Leaf back several years ago - when I arrived, the owner told me that, unfortunately, he might not be able to sell it, because it wouldn't operate anymore. What? I said. What do you mean? He stated that the car would no longer turn ON, would not go into gear, of course, and he had to even use his 'physical' key to even unlock the door.
I told him I would still take the car, at a slight discount, since I had an idea of how to 'solve' the issue.
I pulled my 2014 Ford Focus up to the side of the Leaf, attached my battery cables to both car batteries, and the LEAF immediately was able to be turned ON. I left it on to charge for a few minutes. I then unplugged. I then sat in the LEAF, and put it into Reverse, to move out of the driveway, for a test drive. It would not. It was ON, but it would NOT go into gear.
The simple 12v battery is the culprit.
I removed the 12v battery, took it down to Sams, traded it for a new one, came back, installed it, and the Leaf then not only turned ON, but went into Gear, and has PURRED LIKE A KITTEN ever since.
The $100 price discount paid for the replacement battery, but also gave me a three-year warranty on it : )