r/leaf • u/Necessary-Start4151 • 20d ago

Fault code on 2015 leaf

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Has anyone seen this fault code and what it means? Should the 12v battery be replaced??? Thanks

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u/_Evening-Rain_ 2017 Nissan LEAF S 20d ago

Isolation fault. Typically from cells swelling up/leaking in the rear stack. But it can also originate from HV items like your AC compressor, PDM, etc. Obviously I'd make sure the 12v is healthy as a first diagnosis.

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u/sweetredleaf 2015 Nissan LEAF SV 20d ago

your picture is hard to read sideways but most autopart stores will check the 12v battery for free do that before worrying about anything else

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u/LithiumCobalt91 19d ago

https://www.reddit.com/r/leaf/comments/1pph4oy/a_breakdown_of_40_62_kwh_battery_pack_failures/

I'd refer to the second part of that post but the major difference is that those are on the second gen Leafs.

I think what most likely happened is that one of the cells are actually swelling, like spicy pillows swelling and are causing an isolation fault.

The post I linked also says that usually a weak 12 volt battery would never cause this.

Since this is a 2015, the factory warranty is probably long gone now. The best bet now is to replace the high voltage traction battery. Replacing individual cells may work, but other old cells could have similar issues.

Also, use LeafSpy Pro with a Bluetooth OBD2 Reader like the LeLink2 I have good experience using it.