BMW Key Battery
This answer is applicable for many BMWs in addition to the one listed below.
car year: 2002
car model: 330Ci
The remote feature quit working on my key I got the spare key and it works fine.are the batteries replaceable in the key?
On the later BMW models that have the trapezoid (or diamond) shaped key head, the battery in the key is rechargable and is charged when the key is in the ignition. The battery is not replaceable. We would suggest that you have the BMW dealer check the key. It may just need to be reprogrammed. Otherwise, the key will need to be replaced (via the BMW dealer).