Battery voltage sensor "K" low voltage. Since it's a new code after you've been in the pack I'd wonder if you left the sensor wire off this cell. If you can get a scan tool with live data then look at your cell voltages and gather some information. When I went into my pack, I found the copper cell connector straps were green and oxidized. I opted to spend $30 for new ones with a nickle plating rather than clean them. I had codes for multiple cells but they all turned out to be good, just bad connections. Clean your cooling fan, ducts, and filter for the HV battery pack if you blew up a cell to ensure you have good thermal management of the pack. You can remove the screen and buy one that snaps over the inlet vent to make future service easy.