this works for e46 318i used twice now 6/5/2015
Remote Key Re-Initialise – If a key fails to operate remotely, it will have to be re-initialised (all keys in sequence at the same time)

1. Get in and “close all doors”
2. Turn ignition on & off quickly (no more than 5 seconds) to start the process. Next action must take place within 30 seconds

3. First key – hold down button #2 (unlock) while striking button #1 (lock) three times. Release button #2. Confirmed by door lock operation.
4. If you have more than 1 key then you need to repeat for the other keys within 30 seconds of first or they will be rendered inactive.
5. After last key then cycle the ignition on/off to \nfinalise the process (not necessary to start the engine.

Both keys should now have new “randomly selected” security “code words” – asigned by the car’s system.
Those codes will be continuously incremented within the new sequence each time you hit a button. It is when they get out of sequence with the car that they loose the capability to be recognised and you then have to do this again.

That occurs when you take longer than 1 minute changing the battery, or if you hit buttons more often the 1000 times when it is out of range of the car.

X5, E46 & E39 Diamond Shaped Key
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.
\n5.***** \nWith the \nnew 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 \ndone!!
\nAlternate procedure if above doesn’t work or if you do not have a working \nremote:

1. turn key to position 1 five times very quickly
2. remove \nkey
3. Hold unlock button then press lock button 3 times, release unlock \nbutton.
4. If you have another key do the same button pressing within 30 \nseconds
5 turn on ignition to finalize
\n*
\nOlder 3 Button Key
\nRemote Key Re-Initialise – If a key \nfails to operate remotely, it will have to be re-initialised (all keys in \nsequence at the same time)

1. Get in and “close all doors”
2. Turn \nignition on & off quickly (no more than 5 seconds) to start the process. \nNext action must take place within 30 seconds
3. First key – hold down \nbutton #2 (unlock) while striking button #1 (lock) three times. Release button \n#2. Confirmed by door lock operation.
4. If you have more than 1 key then \nyou need to repeat for the other keys within 30 seconds of first or they will be \nrendered inactive. “,1]);//–></SCRIPT>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 ignition to finalize