I went to drive the 540i tonight but the remote button on my key wouldn't unlock the doors. At first I thought the battery inside the key was dead because the remote wouldn't open the trunk either. Then my wife pulled out her key and it didn't work either.

So I inserted my key into the drivers door and it was able to unlock all the doors. Everything seems fine now, but I'm still curious as to what causes both remotes to stop working? any ideas?

I would guess its going bad and predict you will have more problems.

I went to drive the 540i tonight but the remote button on my key wouldn't unlock the doors. At first I thought the battery inside the key was dead because the remote wouldn't open the trunk either. Then my wife pulled out her key and it didn't work either.

So I inserted my key into the drivers door and it was able to unlock all the doors. Everything seems fine now, but I'm still curious as to what causes both remotes to stop working? any ideas?


I just had the same problem the other day .. but now its working fine .. I just recall that day when it wasn't working it was pretty chilly out .. would the chilly weather have an effect on the remote key? stupid question .. how do you change the battery on the key ...

I would guess its going bad
yes, but what is going bad?

and predict you will have more problems.
that's what I was afriad of. I kinda wanted to figure it out in advance so I didn't get stranded somewhere.

I just had the same problem the other day .. but now its working fine .. I just recall that day when it wasn't working it was pretty chilly out .. would the chilly weather have an effect on the remote key? stupid question .. how do you change the battery on the key ...
hmm, it's been rather cold here lately (for Houston, at least).

I'm not really sure how you change the battery. I'll call my dealer if I ever need to.:embarrasm

Anyone of the motors or anyone of the linkages. The dealer may be able to tell with a diagnostic test. I realize that doesn't help you. I have been looking in the Bentley. If I find anything interesting I'll let you know.

I've had this happen on occasion, but it has always been in a parking lot. I presume that some other emitter was effectively jamming the system.

To change the battery in the key, pop the little rectangle plate off of the back of it, unscrew the backplate, remove battery, install new one.

I had a problem similar to this in my Solara a couple of years ago and it ended up being a bad receiver in the car, not the remote(s).

P.S. Your car is fkin gorgeous.

To change the battery in the key, pop the little rectangle plate off of the back of it, unscrew the backplate, remove battery, install new one.

I had a problem similar to this in my Solara a couple of years ago and it ended up being a bad receiver in the car, not the remote(s).

P.S. Your car is fkin gorgeous.

Some trick key strokes need to be made on the fob to re-set it with the new battery. Also while in the cars ignition so they read each other. I saw a BMW writer do it with my key.

thanks everyone.

It sounds like it's somewhat common and the car probably won't crap out on me soon. So I'll just mention it next time the car in for service.

Anyone of the motors or anyone of the linkages. The dealer may be able to tell with a diagnostic test. I realize that doesn't help you. I have been looking in the Bentley. If I find anything interesting I'll let you know.
Thanks. I wasn't planning to fix it myself (zero maint to 100k). But I figured if I didn't have any idea as to what to tell the service guys to look for that they'd never figure it out, especially since everything seems to be working now.

Based on the responses, I should be able to wait until the next time I need to take it in.

...how do you change the battery on the key ...

don't know what to tell you...it depends on model year...and you don't have any info like a signature or the info many leave in the upper right of their posts as to what model year you have.

Old e39 keys have a battery...e39 new style keys recharge in the ignition. The e34 540i key has 2 batteries and different battery number.

This is the instructions for the old style e34 & e39 keys on how to remove the back...the battery info is for the e39 key...

http://memimage.cardomain.net/member_images/7/web/739000-739999/739005_139_full.jpg

I don't think you can change the battery in your 2003 key but I doubt thats the problem. Try reinitializing the key before you take an expensive trip to the stealer. This is the procedure from bmwtips:

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)

- Get in and “close all doors”

- Turn ignition on & off quickly (no more than 5 seconds) to start the process. Next action must take place within 30 seconds

- First key - hold down button #2 (unlock) while striking button #1 (lock) three times. Release button #2. Confirmed by door lock operation.

- Repeat for second key within 30 seconds of first.

- After last key then cycle the ignition on/off to finalise the process (not necessary to start the engine.

Problems with the automatic entry system are frequently tied to a failure in the fuel door lock actuator or the fuse for that circuit. Do a search...

There are 13 pages in the Bentley on the windows. They are quite involved. If your car has side impact air bags (which ones don't?) you have to be sure to disconnect the battery (a task in itself) before doing anything or you could get seriously hurt.