Resetting the key for the door locks.

I just replaced the battery in the key for my 99 540. How do I reset the key. No manual with instructions came with the car.
Need you help. Thank-You.

To do this procedure you need to have one working key and one key that needs to be programmed.

1. with the both keys, get in the car and close all windows and doors.
2. Put working key into the ignition and turn to position 1 (the accessories should turn on)
3. turn the key back to position 0 and take key out of the ignition.
4. Using the working key, hold down the unlock button, press the Roundel (lock button) 3 times, and release the unlock button. Doors should lock and unlock.
5. With the new key, hold down the unlock button and press the Roundel (lock button) 3 times and let go of the unlock button. Doors should lock and unlock and you're done!!


Alternate procedure if above doesn't work or if you do not have a working remote:

1. turn key to position 1 five times very quickly
2. remove key
3. Hold unlock button then press lock button 3 times, release unlock button.
4. If you have another key do the same button pressing within 30 seconds
5 turn on igntion to finalize

Good luck