E46 Key issue,new battery or re-initialise?

Scania · 18 Aug 2014 at 11:38

The remote door lock/unlock seems a bit awry with my 2000 e46 325i, my regular use key will sometimes lock and unlock the car, sometimes not, when it doesn't though I'm stuck with a car alarm going off and the engine not starting!

It's often fine for weeks at a time and then seems to play up for a day or two then behaves itself again....???

I tried my spare key which is identical in appearance to my regular one, this seems dead but I can manually unlock the door with it (by physically putting it in the lock) and so long as it wasn't locked with the remote previously,the car will start.

I've asked a chap who replaces battery's in car fobs and he's warned me to not change the battery unless I'm absolutely sure it's the problem and not just one of wanting the key re- initialising but, he said if I try to re-initialise a faulty key I could well find myself with a key the car will no longer recognise and me being unable to start the car!

Has anybody else being in a similar situation? I've had this issue previously with both my e38 and e39 but, they had a different key design which was far easier to open to change the battery, on both cars I did it quickly enough to not need the re-initialisation process, my e46 though has a different key (see picture) which from what I've read requires opening up with a craft knife and soldering irons to change the battery....

Part of me is thinking sod it and just unlock the door manually, but, I do quite like the remote function....

Any help appreciated.

rodenal · 18 Aug 2014 at 12:06

I managed to do something stupid (can't remember what) with my e46 key and it lost its programming for the central locking - but at no point did it fail to start the car.

Not convinced re initialising it is going to do anything for you with the main key - try it with the other remote one though. I had to mess around with it a few times before getting the procedure to work

SHEDDER1uk · 18 Aug 2014 at 12:20

Batteries are not supposed to be changed as they are recharged in the ignition barrel. They can be changed when they fail with a bit of desoldering etc if you know what you are doing.

antijoke · 18 Aug 2014 at 12:21

Is this just at one location?

I had this happen on my E46 and it turned out my neighbours had installed one of the DIY doorbells and it was interfering with the frequency of my key and the RCL, they unplugged it and ditched it and the problem was gone.

Stumped me for a week or so. Worked fine at work, and on drives to charge the key, but dead at home.

Scania · 18 Aug 2014 at 13:29

anticonscience said:
Is this just at one location?

I had this happen on my E46 and it turned out my neighbours had installed one of the DIY doorbells and it was interfering with the frequency of my key and the RCL, they unplugged it and ditched it and the problem was gone.

Stumped me for a week or so. Worked fine at work, and on drives to charge the key, but dead at home.

Unfortunately not, it's usually fine outside my house for example yet this morning I woke up the neighbours by setting off the alarm when I opened the door with the key after the remote stopped playing ball again, it had been fine all weekend though....

Gaygle · 18 Aug 2014 at 17:38

Use the spare key for a while and get it charged up from the ignition, then use that key permanently?

Banny · 18 Aug 2014 at 20:52

Got same problem so have opened up my spare got a battery coming so will resolder it in to see if it works.
Off to Italy next week so hoping that will charge my main key as both are flat.

Scania · 19 Aug 2014 at 10:28

Gaygle said:
Use the spare key for a while and get it charged up from the ignition, then use that key permanently?

The spare key has not worked (remote control wise) since I've had the car, it will start the engine though.

Scania · 19 Aug 2014 at 10:29

Double post

Gaygle · 19 Aug 2014 at 12:51

Is that because its completely run down though? Maybe it just needs a charge which will come from using it regularly.

Scania · 19 Aug 2014 at 13:07

Gaygle said:
Is that because its completely run down though? Maybe it just needs a charge which will come from using it regularly.

Don't think so, I used it for a long distance trip recently when my wife had my house (and primary car) keys, it was still dead at the end of the day though.

Banny · 19 Aug 2014 at 17:31

Changed the battery and my spare never worked

Scania · 19 Aug 2014 at 19:47

Tried the re-initialise thing tonight, drivers key seems to work (doors lock & unlock to acknowledge the reset) but it subsequently refuses to lock or unlock the doors, the spare key does nothing at all.

I'm coming to the conclusion there's a fault with the remote sensor in the car maybe, seems fairly common from what I've Googled.....

Looks like I'm manually locking & unlocking the damn thing for the time being! :/

gbradders123 · 19 Aug 2014 at 19:50

re-initialise them both together? you have to do them in sequence. The central locking button has nothing to do with the immobilizer chip.

Atari · 19 Aug 2014 at 19:54

I'd try and replace the battery if it's not already been done. A mates E46 did the same as yours and was very intermittent before dying completely.

There's a guy who advertises on eBay who does new keys for £55 inc coding. Think he's based somewhere in north London.

Scania · 20 Aug 2014 at 06:29

gbradders123 said:
re-initialise them both together? you have to do them in sequence. The central locking button has nothing to do with the immobilizer chip.

Did both keys in sequence, yes.

The drivers key works so far as the door locks pop up & down in acknowledgment of the initialisation sequence (as they should do) but nothing happens when I try the same procedure with the spare key.

Both keys will still start the car but neither will open nor lock it.

The sequence I've been following is this one...

http://www.e46zone.com/forum/topic/1449-how-to-program-your-bmw-remote-key-fobs-to-your-car/page-2