2001 BMW E39 remote stopped working

Associate
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2 Feb 2010
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Hi all, I have a 2001 BMW E39 5 series. My remote control on the key has stopped working a few days ago. At first it just took a few presses to get it to work, as though it was losing power, and now the buttons create no reaction in the car at all. The key still works in the door lock to open and shut the vehicle via the central locking and it still starts the ignition fine.

I did a bit of googling for instructions on replacing the battery, but it seems that from 2001 onwards, this key does not have a battery, and is charged by the ignition everytime it is driven.

I have given it a few days and a couple of journeys about an hour long each to try and charge the key, but no luck, it still does not operate. I only have one key with the remote buttons, my spare doesn't, so I cannot test whether the issue is with the key or the receiver.

Having read about it a bit more, I can't find a decent answer on how to actually fix the problem. I'm hoping some of the BMW experts here will have some knowledge on this problem and some great advice to get me back into my vehicle remotely!

Many thanks
 
Man of Honour
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17 Oct 2002
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If you have the diamond-shaped key, you are correct in that the battery is not replaceable as it's charged by the ignition. Officially, you may well need a new key if this is the problem.

However you can replace the batteries unofficially - but it does involve splitting the key and doing some soldering!

However before you get that drastic check the fuses.

More info..

http://www.bimmerforums.co.uk/forum/f3/save-100-by-fixing-your-key-fob-t1563/
 
Associate
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It is indeed the diamond shaped key. I've read that guide and it warns against trying it if you only have one key, incase you cause more damage. However, I have a second key, but it is only a basic one, with no remote buttons. Do you happen to know if I give it a go, and do ruin it, will I still be able to get another remote key off of BMW?

I also see according to that guide that BMW charge in the region of £100 for a new key, do you know or have any experience if that is still accurate today?
 
Associate
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Yes I've found that guide on re-syncing the key with the car, without having to change the battery, but I don't understand how that could happen, and also not sure how that ties in with the symptoms that the vehicle showed, as the key became gradually unusable over a couple of days, rather than suddenly, presumably, due to battery slowly dying.

However, I'm trying to read up on what damage can be done by doing these procedures before I do anything, as I've never done anything like this before, and not very good with electronics.
 
Soldato
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You cant do any damage by trying to resync it.

A friend of mine picked up a 530i Touring (E39) for about £4.5k a year back. He drove it back from Manchester, came to show me in the afternoon and it was reluctant to unlock. 2 days later it wouldn't open at all. He came over the following weekend and we resync'd using the above method. It's been working ever since.
 
Associate
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Excellent, well I'm having a DIY day on my car tomorrow to get several jobs done and that will be added to my list, hopefully it works as well as your friends as cutting the key open will be a pain.
 
Associate
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So, I did the reprogram sequence, before messing around cutting the key up and changing the battery and it worked... for a little while.

Later that day it stopped working again, so I gave it about an hours drive and tried it again this morning and it worked. Am I right in thinking that as I did the reprogram sequence it will now take a little while to recharge fully before it is back to working normally? Or is this a sign that the battery is on its way out and will need replacing soon?

I don't want to lock the car with the remote, which puts the alarm on, and then when I come back to it, have no power in the remote to de-activate the alarm, as it will go off if I open the car with the key in the door.
 
Associate
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An update for anyone that finds this thread in the future. After having done the reset last week, for the first week I still had to lock the car by putting the key in the door. After driving it for a week it seems to have given the key the kiss of life and it's back to normal, working remotely as it was before now that it has charged up again.
 
Soldato
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19 Oct 2002
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One of my diamond shape keys has stopped unlocking/locking the car remotely, i've used that key for around 200 miles now so it should be fully charged. I've tried the place key in ignition, turn to 1 turn back within 5 seconds, remove hold lock, press unlock 3 times, release lock multiple times and nothing happens, so I opened the key to test the battery and it's showing 3.3volts which leads me to believe the battery is fine.

Am I doing the sequence of reprogramming right, i've read numerous versions of it but they're essentially the same.

Any pointers mike?

Edit: sussed it was pressing the wrong key combination, all working again.
 
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