Before servicing the computer, disable the battery pack in the UEFI BIOS.

1. Turn off your computer and disconnect the ac power adapter and all cables from the computer.
2. Turn on your computer. Press F1 to enter the ThinkPad Setup program when the ThinkPad logo is displayed.
3. Select Config -> Power. The submenu will be displayed.
4. Select Disable Built-in Battery.
5. Follow the instructions on the screen.

Then the battery pack is disabled in the UEFI BIOS. When ac power is reconnected, the battery pack will be automatically enabled.