E39 - 2003 Key fob replacement

[georgost]

Can you change the battery in your key fob. My key fob seems to be working intermittently and can’t seem to figure out how to open this thing.

[bmwm5lover]

I cannot speak for your car, but if it employs the same key/remote as my car, according to the manual, the key recharges as you drive (which is why they recommend you switch between both keys every few months).

Perhaps the rechargeable battery is on its way out? Or maybe there is dirt between the contacts?

From what I've heard a new key is about 200$.

[daveyto]

Originally Posted by georgost

Can you change the battery in your key fob. My key fob seems to be working intermittently and can’t seem to figure out how to open this thing.

Whatever you do.DO NOT REPLACE THE KEY.

The battery can be replaced and yes it can be cracked open with an xacto. I have done it.
The battery gets power when the key is in the ignition and subsequently charges. The key is rechargeable. Are you using a spare key?

If your key is not unlocking or locking, It is most likely not the battery, the issue is probably the BCM. But I need more info to confirm..

[georgost]

Originally Posted by daveyto

Whatever you do.DO NOT REPLACE THE KEY.

The battery can be replaced and yes it can be cracked open with an xacto. I have done it.
The battery gets power when the key is in the ignition and subsequently charges. The key is rechargeable. Are you using a spare key?

If your key is not unlocking or locking, It is most likely not the battery, the issue is probably the BCM. But I need more info to confirm..

What's the BCM? I have two keys. The spare key (wife's key) functions fine. The key that I use everyday will function intermitintly, with me often having to smack the remote a couple of times for it to actually work.

[daveyto]

if one key works and the other doesnt...it may be the battery.. are you aware of the initialization process for the key? Sit in car-close all doors-turn ignition to on without turning the car on-remove the key, then press the open close button on the key 3 times...see if that works if my memory helps me.
re the key:
You can cut the key open with an exacto where the seam is..be careful not cut cut your self. You will need a lot of pressure. I think you can buy this battery on ebay...its a lithium ion I belive, not a nicad.
you can crazy glue it back
The BCM is the body control module...it controls locking and unlocking via the remote among other things.

I dont see how smacking the remote will make it work. as its a solid state device with no moving parts.

[georgost]

Originally Posted by daveyto

if one key works and the other doesnt...it may be the battery.. are you aware of the initialization process for the key? Sit in car-close all doors-turn ignition to on without turning the car on-remove the key, then press the open close button on the key 3 times...see if that works if my memory helps me.
re the key:
You can cut the key open with an exacto where the seam is..be careful not cut cut your self. You will need a lot of pressure. I think you can buy this battery on ebay...its a lithium ion I belive, not a nicad.
you can crazy glue it back
The BCM is the body control module...it controls locking and unlocking via the remote among other things.

I dont see how smacking the remote will make it work. as its a solid state device with no moving parts.

Maybe the contacts for the battery are the issue?