key battery on 2004 BMW 745Li

How to change the key's battery.

Asked by for the 2004 BMW 745Li
If your car is fitted with comfort access you can simply pop the small cutout cover on the back and replace the little round battery, forget the battery part number sorry
2 more answers
just open it up an change it, or bring it to the dealer and they can charge you about 2000.00 dollars to do it.
I need your visa card number