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Jim_C

"Diamond" key - new battery or replace?

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I've just bought a new diamond key from Cotswold BMW, which cost a princely £162 and works a treat (allaying fears of faulty diversity antenna for the time being).

In order to have 2 working keys, I'd like either to have the battery replaced in the old key, or preferably have the blade and transponder put into a new body.

 

Is this possible and would I need to have the old key recoded?

 

Who should I be talking to?

 

So many questions...

 

Many thanks in advance.

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I replaced the batteries in both my diamond keys.  It's not that straight forward as the keys aren't designed to be serviceable and you need to cut them open with a Stanley knife, or some other tool, which is a pig of a job and trying to do a neat job is nigh on impossible.

 

Next you need to desolder the original battery from the PCB inside, kits are available that also include the microswitches and I also did those too.  It's not difficult but it is quite fiddly, especially if - like me - you only have a soldering iron the size of a pit shovel.

 

Obviously the new battery needs to be soldered in place of the old one, again, not difficult but make sure you get it as close to and flat as possible to the PCB or closing the key case again becomes a problem.

 

One key died again soon after - it still starts the car but remote locking functions don't work and manually unlocking the car triggers the alarm, that probably happens anyway.  The other key has been fine ever since, though.

 

However, that said, they both look a mess, one is marginally better than the other.  You don't have much choice but to glue the two halves of the key case back together, and just like cutting them open there's no real way of doing it so that it isn't visible, and visible in an ugly way.

 

I didn't need to recode/reprogram the keys but I don't know if I just got lucky or if it's just how it is.

 

I have been intending to get new keys but the cost is prohibitive.  There was a BMW specialist in the south east who used to do a pair of keys for £99 or so but I'll be damned if I can remember their name.

 

Hope this helps and best of luck.

 

PS, transferring the blade to a new body is pretty much impossible, unfortunately.  The blade and one half of the diamond body are moulded together and I don't see a pragmatic method of separating them.  You could buy a new blank and have that cut to match the old key and then transferring the innards would be simples, but I couldn't find anywhere willing to cut the blank.

 

Even Timpsons, who claims they will cut any key for any car, refused with the excuse that the metal the key is made from will damage the cutting machine.

Edited by Haych

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Wow! Thanks for the comprehensive reply, Haych. 

In addition to the existing problems, my soldering skills are nil. At best. I'm hoping there are professional solderers (mercenaries?) who will do it for me...

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I’m pretty good at soldering having once done it for a living. I’ve since upgraded my soldering kit too. I’m sure there are plenty of people who’ll do it for you - if you live close enough I’d be happy to help out. 
 

If not don’t let anyone overcharge you, it’s not a massive job. Getting into the key to start with is by far the hardest part. 
 

Best of luck, hope you get it sorted. 

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I've sent the key (along with our similarly dead rechargeable blue Transit minibus key) to a seemingly reputable company in Lancashire, who promise to service, repair and replace faulty bits for £25/key. I'll report back once the keys return...

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17 hours ago, Jim_C said:

I've sent the key (along with our similarly dead rechargeable blue Transit minibus key) to a seemingly reputable company in Lancashire, who promise to service, repair and replace faulty bits for £25/key. I'll report back once the keys return...

Please do. That's sounds much better than messing around doing it myself. Will it still be programmed when it comes back? Don't think this is hard to do yourself if not... 

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As far as my research has gone, I believe that the key will still be programmed when the battery is replaced. A friend from another forum has bought a diagnostic kit from BCables, which I'm tempted to get for all the inevitable minor issues.

 

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I have just replaced the battery on a diamond key fob. The replacement came from  here https://www.ebay.co.uk/itm/GENUINE-REMOTE-KEY-BATTERY-ML2020-For-MINI-BMW-M-X-3-5-X3-X5-X6-E39-E46-VL2020/392249943002?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

As has been stated you have to open the case which can be a problem.

Once the board is out removing the old battery means unsoldering the old battery and  resoldering the new one on place in place.

It will need to be re-initialised  to the car again the instructions are easy to find on the net.

Pleased to say I now have two working fobs.

 

Edited by simufly

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Sounds like you got a decent service, simufly.

My keys arrived back today (I posted them on Monday, so that is rapid service).

They arrived with a piece of paper explaining that they will need to be re-synched in order to work. So, I'll have a go when I'm less knackered.

 

 

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I used a place in Doncaster, remote keys I think for another car £15 a key posted

Very fast turn around & a brilliant service, my worn looking key came back looking like new

& worked flawlessly for two years before I sold the car.

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9 hours ago, dirtydirtydiesel said:

I used a place in Doncaster, remote keys I think for another car £15 a key posted

Very fast turn around & a brilliant service, my worn looking key came back looking like new

& worked flawlessly for two years before I sold the car.

Brilliant. I'm in Donny. Where was that at please? 

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Well, I'm not sure if it's me or the key, but I can't get the refurbed one to work remotely. The blade still works to lock/unlock and start the car, but it still triggers the alarm and none of the buttons work. I've tried several versions of the synching ritual of turning the key and pressing buttons, to no avail...

Edited by Jim_C

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8 hours ago, JasonH said:

If you're lucky the refurbed one might just need charging up. It charges whilst you're driving the car. You'll need at least 40 mins.

Or you can leave it overnight on a rechargeable toothbrush charging base.

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On 7/25/2020 at 5:33 PM, dirtydirtydiesel said:

Or you can leave it overnight on a rechargeable toothbrush charging base.

Does this actually work? I've seen a rather long video on the subject by a somewhat eccentric chap with a similar issue on a Ford Transit blue key. The jury appeared to be out...

 

I've just invested in INPA software and cable, so hopefully that can rekindle the love between car and key. If I can work out how to use it...

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Apparently so, but you could just open the car with the working key & use your repaired

one to start the car & go for a good drive, the rechargeable battery is charged whilst you drive.

Just not sure how long it would take to fully charge it.

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Update...

 

The diamond key still works as before - the blade opens the door and starts the car, but triggers the alarm. No remote functions. I think the battery in the remote is fine.

 

I've tried the "Key in ignition, switch to position 1 and back, remove key, press and hold..." routine many times - it's not working.

 

I've now had a brief look at NCS Expert, but I haven't been able to find what I (think I) need. 

 

Is there anyone around with experience of how to find out if the remote on my key can be made to operate the central locking (and disarm the alarm)?

 

I'd be super grateful for any advice on how to proceed...

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Basically with a new battery the key should pretty much work out of the box. It was possible the new battery was flat but you've tried to charge it now.

 

If it doesn't work then you need to go back to the place that changed the battery - either they didn't do it properly or it wasn't the battery that was faulty. If one fob works and the other doesn't then it's not the car it's the key.

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For what it's worth I have the same issue, I have one key that remotely locks the car, but the other will not work no matter how much I charge it or try to sync it. Battery has already been replaced. I would also be keen if anyone knows how to look at key info in INPA.

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9 minutes ago, edd_jedi said:

For what it's worth I have the same issue, I have one key that remotely locks the car, but the other will not work no matter how much I charge it or try to sync it. Battery has already been replaced. I would also be keen if anyone knows how to look at key info in INPA.

 

Sounds identical to my situation.

 

When I bought the car, the old key (the one I can't get to work remotely) would switch the radio to Heart (WTF?) and move the seat when I put it into the ignition, so clearly it had some kind of comfort programming going on. Since getting the new key, it doesn't do this (I think BMW might have erased the comfort settings for all keys when they programmed my new one).

 

I feel that there should be some way using NCS Expert to view the settings and/or activate the remote locking/unlocking on the fob (provided, of course that it isn't otherwise faulty), but I'm just not sure I'm up to the job without guidance (Jim's skills: nicht_aktiv).

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On 23/07/2020 at 15:31, dirtydirtydiesel said:

Through EBay,  just type in bmw remote key repair & search through the listings for 

remotekeys101 is the sellers id.

Thank you. 

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Sorry to bump an old thread, but I've just replaced the battery in my diamond key, and it's also still not working to remotely unlock the car. I have tested both the original battery and the 'new' replacement with my multimeter, the original battery is reading 0 (is that even possible to be 100% drained?) and the 'new' one is only reading 0.16v, it should be in the region of 3! Is it common for these replacement batteries to arrive completely flat? I tried leaving it on my toothbrush charger overnight but that made zero difference, so that is confirmed as a myth. Will it even be possible to drive the car for long enough to completely charge the new flat battery?

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Yes new batteries can be discharged if they have been in stock for a long while. 

 

This might work to get the key charged... Put the car on charge. Put the key in the ignition and turn it on. I think you'll need at least position 1, probably position 2. Leave it for 45mins.

 

The car battery will need to be charged for a while to recover but the key should have got some charge in it. 

 

Years ago I think I saw that they key charged in 45 mins. 

Edited by JasonH

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