Many BMW keys can unlock doors remotely, activate the alarm and open the boot. Sometimes changing the key batteries or having certain maintenance on the vehicle may require the key to be reprogrammed so the car and key are on the same frequency to communicate with one another.
Determine Your BMW Key
Determine what type of BMW key you own. Modern BMW keys with remote access come in two types. One has a large, rounded rubber head, and the other has a diamond-shaped head with the BMW emblem in the centre. Knowing the type of key you have will ensure success when reprogramming the remote control, as the buttons on each key are located at different places.
When reprogramming your key, the transmitter and remote control must be initialised. Enter your vehicle and close the driver's door. Insert your key into the ignition while turning it to position "1" and then turning it back to position "0." (Position 1 usually turns on the radio, position 2 activates the computer system without cranking the car and position 3 starts the car.) The numbers will be etched in the ignition so you will know the position to which the key needs to be turned. Remove the key from the ignition and press and hold down the button that unlocks your car (the button on the far left of the key). Keep the "unlock" button pressed while you repeatedly press the BMW emblem button that locks your doors. You must press the BMW emblem button at least three times within 10 seconds. After you remove your finger from the lock button, the LED light on your BMW key will began to flash for approximately 10 seconds. The locks in the car will lock and unlock to indicate you have successfully reprogrammed your key.
Insert your key into the driver's side door to unlock all doors. Once you are in your car, insert the key into the ignition and turn it to position 1 and then switch it off. Make sure you perform this task within five seconds of entering the car, otherwise the system will not recognise that you are trying to reprogram the key. Remove the key and press the "unlock" button and keep it held. Press the BMW emblem button three times within 10 seconds while you still have your "unlock" button pressed down. Remove your finger from the BMW emblem button. Your central locking system will immediately lock and then unlock to let you know the procedure was successful.