Key Fob stopped working all of a sudden. Hello Bimmer Gurus! I have a 2011 535i xDrive with comfort access and 56,xxx miles. The vehicle has always been a nice drive and everything works. Two days ago, went to get a hair cut, came out and couldn't open my doors normally with the fob is my pocket. Took the fob out and tried to manually open it HOW TO REPLACE KEY FOB ON BMW F10 F11 F30 F31 F32 F36 X3 X4 X5 X6 BMW PARTS: Put the new battery back in it with the positive side up, and refit the cover. Slide the tab on the bottom of the cover into the fob and press the cover down. Then, slide the key back into the fob and test out the buttons on the fob. If they work, carry on with your BMW ownership. If not, the remote may be damaged, or you simply put the battery #x3keybattery #x3mkeybatteryHere is how you change your BMW X3 or X3M Key battery. This is likely the same for the X4 or X4M. Go ahead and do both keys when Product description. 1 battery for BMW F series remote key buy here a lithium button cell with extra long durability for your BMW remote key. Suitable for all BMW F models. These batteries have a diameter of 24 mm. (CR2450) Battery regulation: waste batteries and old batteries must not be disposed of via normal household waste. Hur man byter batteriet till bilnyckel, BMW F11 (F10) en DIY video. Make sure to subscribe= After these terminals are connected, now you can press your remote key fob boot/trunk open button. This should open the electrical latch of the boot and now you can open the boot/trunk as shown in the following photo: Now, after you have opened the boot, first disconnect this external battery. Then reconnect the car’s own battery. BMW Key EuRhr.