Originally Posted by Zeichen311

The Comfort Access keys have non-rechargeable batteries and a little access panel to allow you to replace the battery when it dies.
Non-Comfort Access keys have rechargeable batteries that cannot be replaced without disassembling the fob.
OP stated in post #4 that he does not have CA therefore advice to inspect/replace the battery is unhelpful. (Also, the rechargeables in the keys easily last over a decade with normal/regular use.)

Also, FWIW: http://www.bimmerfest.com/forums/sho...6&postcount=18.