The BMW keyless entry remote replacement battery CR2032 can be purchased at any auto parts store or convenient store for less that $5 for a pair.
After you have inserted the new battery in the key fob with the positive side up you can push the plastic battery cover back into place and test your remote to make sure it is working.
Troubleshooting: If the key fob is not working after the battery has been replaced try inserting it into the ignition for 20 seconds,
this may synch the key fob to the BMW again. You may also need to have your spare working key fob in the vehicle at the same time in order for it to synch. (Please do not quote me on this
synching method as I read it somewhere else and it would only work with a key fob that is matched to your VIN number already) If the key fob is still not working make sure you do not need to
replace or fix a
blown fuse or relay somewhere or that you did not put the battery in upside down.
The CR2032 coin battery is made by Energizer, Duracell, Panasonic, Maxell, Sony and Philips and can be purchased at Discount Auto Parts, Advanced Auto Parts, Pep
Boys, Napa, Walmart, CVS, Wallgreens, Target and other retail stores. This guide on how to change the battery in a BMW key fob may be useful to owners of the F20, F21, E81, E82, E87, E88, 114i, 114d, 116i, 116d, 118i, 120d, 125i, 125d,
M135i, E90, E91, E92, E93, 316i, 320i, 320xi, 328i, 335i, 335is, F22, F23, 228i, 235i, F32, 428i, 435i, 420d, E60, F10, 528i, 535i, F12, F13, 640i, 650i, 640d, 650i, F01, 730d, 740i, 750i, 740Li,
750Li and xdrive. The The functions of the BMW key fob will unlock or lock your doors, open the trunk, roll your windows down and open your sunroof and sound your panic alarm if needed when
working properly. If you own a Toyota you can go here for instructions on How to Replace the Battery in a
Toyota Key Fob. Please refer to your owners manual for proper OEM replacement information and recommended maintenance intervals for your specific vehicle. If you BMW key fob is losing range
and won't unlock or lock your vehicle for a distance you probably need to replace the battery.
Please see the How To Replace the Battery in a BMW Key Fob for instructions on changing a dead key fob
battery and BMW Maintenance Guides for more helpful repair instructions.