My 2003 BMW 525i key remote suddenly stopped working. It will not open doors trunk etc.. Any help in this matter will be greatly appreciated.
Your key may have lost its initialization. To reinitialize a key, you need to take all of your remote key and print these instructions out and jump in the car. Make sure all of the doors, hood, windows, trunk and sunroof are closed. Then make sure all of the doors are unlocked. Turn the key to just the radio position (just until the radio turns on and the airbag light is on). If the service engine light comes on, you have turned the key too far, and you need to start over. Once you turn to the radio position, turn the key off and pull the key out. Press and hold the unlock button of the remote, then press the lock button three times. At this point the locks of the car should lock and unlock. If this does not happen you need to start over. If you have another key you should initialize that key by starting at the the point of pressing and holding the unlock button, until the doors lock and unlock. Then the key should work again. The entire process with two key should take no more than 30 seconds. You may have to practice this a few times to get it right. I would suggest bringing the instructions with you in the car while doing them. If you have to start over to try again, take the key out of the ignition open and close the drivers door and start from the beginning.Your body style car has the tendency to pop the fuel door lock actuator fuse. To see if the fuse is blown you can simply lock the car and see if the fuel door locks. Then see if it also unlocks. If it works you should have no problems. If the lock does not work you will not be able to initialize the keys, because the fuse is also the same fuse for the antenna that gets the signal form the key. Find the fuse that is blown in the right hand side trunk compartment and replace it. You can do one of two things to make sure that it does not pop again. Unplug the fuel door lock actuator, or replace the the actuator. The actuator is located at the end of the little green emergency release cable also in the right side of the trunk compartment. They have change the fuse number through certain model years, so I do not remember which fuse it is but I think it is a 7.5 amp fuse. Once the fuse pops the keys will have to be reinitialized once the fuse is replaced.
Another reason why your key does not work is because it is just flat out broken, and unfortunately this is the costliest repair as the dealer is the only one who can get you another one. If you have done all of the above steps and your key still does not work then your key is probably bad. But I would not guarantee it. It may have to be checked out. If you have two keys and one initialized and the other did not, then I am pretty sure you have a bad key. Just remember to read, and try the initializing steps a few times as it may not work the first time.