Open your MacBook pro. Unplug the battery connector and plug it right back in.
Remove charger from your MacBook Pro and remove screws from the bottom of your MacBook Pro.
Remove the lid. There is a little cable going from the battery to the connector on the motherboard (low right corner).
You just need to unplug it and plug it right back in.
Note : Do not remove your MacBook Pro battery or touch anything else on your machine.