2002 BMW 3 serires key batteries

David:

Poppycock! I see you are educated in reading the dealer's smirk.

I have a 3 Series and replaced the batteries in the keys. I believe there are two different types of keys. For mine, there is a small indent where a screwdriver can be used to pry the back off key. Then remove two small screws that hold the battery(s) in place. Batteries (nothing special) are available at your local drugstore in the watch battery area. I have a set of small screwdrivers (jeweler's screwdrivers) from Radio Shack cost able $3 bucks.

********************************** Tom Caines "The Answer is Always Yes" **********************************

"Tom Caines" wrote

Yes, somewhere around 2000 the newer keys were introduced which have a rechargeable battery in them. It gets charged every time you put the key in the ignition. From all I've read, those batteries are not replaceable.

Pete

How do you tell? Take the battery out and read the battery's "code" number?

There is no way to take the new keys apart - so there is no way to replace the battery or take it out and read it's "code" (whatever that is..)

How do you know the batteries are dead? Because the remote does not work? Not the best test...from my experience. One of my remotes was not working, due to non use of about one year. I thought the battery was dead too. Then I went through the programming sequence with the dead key ...lo and behold the dead key began to work.

My experience has been that these keys go through some self atrophy.

Instead of buying a new key, first go through the programming sequence. Make sure you program both keys at the same time. And monthly alternate using keys. Because they are recharged in the ignition.

I did not see where the key could be opened.

Gamini Weerasekera.

I have the same problem with keys for a car I bought - they had not been rotated, so one is fine and the other is flat and whilst it works mechanically did not work after recharge.

How do you reprogram it?

I know this works for E46 models. Note ALL keys must be re-programmed at the same time.

To initialize the keys, proceed as follows: Enter the vehicle

1. and close the doors.
2. Briefly (max. 5 seconds) turn the ignition on and off again.
3. Remove key; press and hold "unlock" button. While holding "unlock"
4. button, rapidly press "lock" button 3 times within a period of 10 seconds.
5. Release "unlock" button. The LED flashes slowly for a maximum of 10 seconds. The central locking system activates and releases all locks in rapid succession to indicate that the initialization procedure has been successful. If LED continues to flash or if the locking system fails to respond, the initialization procedure will have to be repeated.
6. To initialize additional remote control keys (make sure that no more then 30 seconds elapse between each initialization procedure) repeat steps 3 and 4.
8. Note: The ignition does not have to be cycled on/off for additional key initialization.

Lemuel Johnson

No LED on my 735i keys :-(

No LED on my 2005 E46 key either

The programming sequence is correct for ones without the LED too.

1. Release "unlock" button. The central locking system activates and releases all locks in rapid succession to indicate that the initialization procedure has been successful.

Now to initialize additional remote control keys (make sure that no more then 30 seconds elapse between each initialization procedure) repeat steps 3 to 5.

3. press and hold "unlock" button. While holding "unlock" 4. button, rapidly press "lock" button 3 times within a period of 10 seconds.

1. Release "unlock" button. The central locking system activates and releases all locks in rapid succession to indicate that the initialization procedure has been successful.

Or on my 2003 Z4 (E85) key. But my '99 E46 key has an LED - and a replaceable battery.

Tom K.

...or my wife' '02 E46...

-- Larry