2001 E39 Key Battery Replacement

frydaddy · Aug 7, 2005

Greetings,

One of the keys for my 2001 530 has gradually stopped working. The Bentley manual shows how to replace the battery in pre-2001 models, but says that from 2001 on the battery recharges while the key is in the ignition. I think that this one is dead since all batteries (this one's probably lithium) have charge-cycle limits. I hesitate to start trying to pop the key apart. Any advice on this?

Thanks ...

DanT · Aug 8, 2005

Its not a battery but rather a charge capacitor that is recharged by being in the ignition. They do sometimes go bad and I dont know a way of bringing them back to life other than replacement. Maybe somebody else here does.

DT

bluebee · Feb 9, 2011

DanT said:
Its not a battery but rather a charge capacitor that is recharged by being in the ignition.

I'm confused.

Is the "thing" in the diamond key that is charged a battery or a capacitor?

MatWiz · Aug 8, 2005

Try using this key a lot. It might charge it back to full charge.

NFS · Aug 8, 2005

Use the bad key on the next long trip. I have heard of people bringing their key back to life after an hour or so of charging. Worth a try!

chivas · Aug 9, 2005

it rumored to take 30 continuous hours of use to fully charge it but a 4 or 5 hour trip should be good and make that a daily key for the next 6 months.

frydaddy · Aug 10, 2005

Thanks for all of the responses ...

Thanks to everyone for your input. I'll try to charge it back up. I haven't driven for even an hour in a couple of months due to an injury. Funny thing is, the key that I almost never use still works fine. Sure hope this works; I just called a BMW dealer and they want $125. for a new one.

DanF

P.S. To DanT :madrazz: : you learn something new every day. I just embarrased myself by insisting to the service rep that the key held a battery .... Didn't know about the use charge capacitors.

frydaddy · Aug 10, 2005

Follow-up question

Does anyone know what positions the key would charge in? I was wondering If I could just leave it in the ignition for awhile, but I doubt it ...

Dan F

chivas · Aug 10, 2005

frydaddy said:
Does anyone know what positions the key would charge in? I was wondering If I could just leave it in the ignition for awhile, but I doubt it ...

Dan F

acc

frydaddy · Aug 10, 2005

The fix

I re-initialized the key and it works now. Should've tried that it the first place. I still can only get one or the other to work though. I do the two keys one after the other but only the one most recently done is working. Not really a big deal, but ...

Dan F :thumbup:

jburnham · Oct 16, 2007

frydaddy said:
I re-initialized the key and it works now. Should've tried that it the first place. I still can only get one or the other to work though. I do the two keys one after the other but only the one most recently done is working. Not really a big deal, but ...

Dan F :thumbup:

Make sure you aren't sticking the second key in the ignition - I did that the first couple of times I tried it. I also tried using my Sonicare toothbrush recharger (charges by induction like the keys) to charge up my keys. They are both working great, but I'm not sure whether it was the re-initializing or the charging that fixed them.

franzdom · Aug 14, 2005

We going to say that but you said "gradually"

jbollier · Aug 18, 2005

frydaddy said:
I re-initialized the key and it works now. Should've tried that it the first place. I still can only get one or the other to work though. I do the two keys one after the other but only the one most recently done is working. Not really a big deal, but ...

Dan F :thumbup:

How do you re-initialize the key? I have one that will lock but not unlock or when you lock the doors with the button on the key you will have heXX unlocking it with the other key

Kev6eel · Mar 26, 2007

E39 Remote Key Not Working (battery dead?)

Both my keys have eventually given up working the remote locking/alarm. Mine are the rechargeable type that are no longer holding their charge. Yes, the later key types are not normal battery but use a rechargeable cell.

Boldly, I took one apart and found the following:

The key's cell is a Panasonic VL2020 (it looks like UL but is VL) which is a rechargeable 20mAh Lithium one with BMW specific solder tags. It is possible to purchase a VL2020-1HF from good battery outlets, but this will need to be slightly modified to solder onto the key PCB. Over here (UK) I got one off eBay for ***163;6 and fitted it myself. A lot cheaper than the ***163;100 my BMW dealer wanted for a whole new key.

Job Done!

BTW, to reinitialise key with new battery do the following (and do same with other remote keys in quick succession to gain same new wireless lock code)

(from http://www.bimmerfest.com/forums/archive/index.php/t-80489.html)

I watched the tech perform this sequence:

Key in ignition
On and off five times - quickly
Removed key - held at shifter level
Pressed Unlock button and held while pushing lock buttons 3 times
Doors signalled confirmation
REPEATED ENTIRE SEQUENCE
Turned ignition on to finalize

This process voided the key that I didn't have me, so if you have two keys, as mentioned above, you may need to repeat for each key within required time to keep code between keys.

Mattrix · Oct 9, 2007

2003 325xi key is doing this as well. I am almost certain the cap is going out because it will work a few times after a long trip but dies within a day or 2. I have popped the cover and found that it is def a VL2020 with a "special" BMW tab configuration. I am looking to buy a replacement but cant find that tab configuration anywhere.

Kev6eel: Is the VL2020-1HF the "H" tab abd if not, what tab configuration worked for you?

jpar · Oct 16, 2007

Key Battery diagrams

I found some details on this battery from Panasonic. They offer it in several different tab configurations and it is likely that one of them will be a close match for the key battery. As I have not taken mine apart yet, I would appreciate it if you could look at the diagrams and tell all of us which configuration best fits this application.

http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_Lithium_VL_TabConfig.pdf

doru · Oct 16, 2007

A few days ago, a thread touched on the subject:
http://www.bimmerfest.com/forums/showthread.php?t=236759
Post#5 in same thread has the DIY to change the rechargeable battery & the link to buy the battery.
Hope this helps

ilian007 · Sep 10, 2008

Ok here is what happened with my keys. When I bought the car the previous owner told me one of the key never worked Key1, but the other one works great Key 2.

Key1 actually worked time to time ..
Key2 stoped working or worked only 30 minutes after I drove the car with it

My resolution of the problem:
Key1: After I opened the key (cut it with sharp knife) and meassured the battery 3.3v-which is totaly ok- I saw the original metal holder of the panasonic battery is broken. There are 2 dots that suppose to keep the metal holder in touch with the battery. First i tried to solder it in many different ways, but none was as successfull as I wanted (the battery surface is not soldarable). Finaly I changed it with one 3.3v battery which I had. To find apropriate battery you use the other posts. it is something panasonic 2020 .. first digits are for the battery capacity 20mAh in that case and second digits for how wide it is. for our case it is 20 which is 2mm. basicly you can put any batter 3.3v 20mAh and 2mm wide I've put 3.2mm 2032.. and was still ok to close the key1 normally.

Key2: the battery was 2volts so i just changed it with another one. has to be minimum 2.9-3v. New one is 3.3v no matter it says 3v on the package.

feel free to contact me if you have any questions. about the battery replacement it is pretty easy if you have basic soldering skills

nigel_1981 · Sep 11, 2008

Slightly off topic

Excuse my ignorance but.. can we reinitialise a key from any E39? Like from a wrecked car? If so, can we also use a car from other models? eg. E36? I realise the key itself wont fit but don't care about that.

QSilver7 · Sep 11, 2008

nigel_1981 said:
Excuse my ignorance but.. can we reinitialise a key from any E39? Like from a wrecked car? If so, can we also use a car from other models? eg. E36? I realise the key itself wont fit but don't care about that.

Yes...the DWA feature (remote lock/unlock) of our keys is not car or VIN specific like the EWS (immobilization feature) of the key.

As long as the orphan key uses the same radio frequency (i.e. in the USA our keys are 315 MHz...in Europe they are 433 MHz) it can be programmed to lock/unlock your car (remember it will never start your car without having the embedded chip programmed with your car's VIN specific ISN (individual serial number)...which ONLY comes from BMW.

Another thing to remember is...the newer style "diamond-shaped" key does NOT have a replacable battery and is kept charged when it is inserted into the ignition and turned to position 1, 2, or 3. If your car was built BEFORE 9/99...it DOES NOT have the capability to keep that key charged...and if your car was built AFTER 9/99...the key probably won't be able to be inserted into the ignition past POSITION 0...which means even though your ignition has the ability to recharge the key...the key isn't cut for your car so the ignition won't turn.

That leaves you with using an orphaned old style rubber headed key from an e36/e39/e38 built before 9/99.

Hope this makes sense...see instructions below on how to program one of these keys to your car...REMEMBER to bring ALL of your master remote keys with you to program them ALL in the same session. Any remote key that you don't do in the same session...will no longer lock/unlock your car.

Stick ONLY the 1st key into the ignition...any other remote key that is to be programmed...start on STEP #3

QSilver7 · Oct 31, 2008

Yes...the DWA feature (remote lock/unlock) of our keys is not car or VIN specific like the EWS (immobilization feature) of the key.

As long as the orphan key uses the same radio frequency (i.e. in the USA our keys are 315 MHz...in Europe they are 433 MHz) it can be programmed to lock/unlock your car (remember it will never start your car without having the embedded chip programmed with your car's VIN specific ISN (individual serial number)...which ONLY comes from BMW.

Another thing to remember is...the newer style "diamond-shaped" key does NOT have a replacable battery and is kept charged when it is inserted into the ignition and turned to position 1, 2, or 3. If your car was built BEFORE 9/99...it DOES NOT have the capability to keep that key charged...and if your car was built AFTER 9/99...the key probably won't be able to be inserted into the ignition past POSITION 0...which means even though your ignition has the ability to recharge the key...the key isn't cut for your car so the ignition won't turn.

That leaves you with using an orphaned old style rubber headed key from an e36/e39/e38 built before 9/99.

Hope this makes sense...see instructions below on how to program one of these keys to your car...REMEMBER to bring ALL of your master remote keys with you to program them ALL in the same session. Any remote key that you don't do in the same session...will no longer lock/unlock your car.

Stick ONLY the 1st key into the ignition...any other remote key that is to be programmed...start on STEP #3 or STEP #4 depending on which type of key you have.

(Instructions to reinitialize old style key)

(Instructions to reinitialize new style key)

Josh P. · Jun 25, 2012

QSilver or someone else:

My Master key will not remotely unlock the doors, though it will manually unlock them and will allow the car to start. My other key works normally.

I had the Master in the ignition for 4 hours straight on a trip and it did not re-charge.

So, before I follow what is below for the new style key, will this even work, or is my key now totally dead in terms of remote locking and unlocking? I'm not sure how it got into a situation where it is still recognized enough to start the car but won't engage the remove lock/unlock feature, but there it is. What I'm afraid of is that the capacitor is dying and I'm going to end up driving somewhere and then having the car not recognize the key and refuse to start.

But if what is below will work, I'd rather do that than spend $150 for a new key.

gilbuzz · Sep 12, 2010

Battery or buttons?

Open the case, but before you replacing the battery check the voltage.( 3v and 2.75v with any button depressed.) If the voltage is within this range the button switches maybe the problem. Use a contact cleaner on each switch while pressing on and off until they begin to functional properly. As an added measure, spray entire PC board to clean components. This worked for me on two completely non functioning remotes.

540 M-Sport · Oct 15, 2010

gilbuzz said:
Open the case, but before you replacing the battery check the voltage.( 3v and 2.75v with any button depressed.) If the voltage is within this range the button switches maybe the problem. Use a contact cleaner on each switch while pressing on and off until they begin to functional properly. As an added measure, spray entire PC board to clean components. This worked for me on two completely non functioning remotes.

Great idea! I have one older remote (much used) and it started being unreliable at unlocking or opening the trunk. Works fine for locking...and it only acted up a couple times. I swapped to my unused (but several years old) remote for now. But will try cleaning the contacts on the heavily used one. If "no go" then I will try replacing the rechargeable battery as outlined above.

borderchris · Sep 12, 2010

Uhhhhhh... very nice and all, but you're responding to a 5 year old post...

energizedmortal · Oct 15, 2010

it can be ten years later they'll always be a newbie that can use this information to make life easier like me... contact cleaner worked thanks

Lucwarm · Oct 28, 2010

I tried this but it seem as the unlock butoon doesnt work. the lock and truck works fine. the unluck button doesnt fseem damage. It work fine prior to the batter going dead. any questions.

Severe550i · Oct 28, 2010

It's funny how and when things happen...
I thought my key might have finally died and was ready to order a new one for $150 from the dealer. Figured I'd try to re-initialize first, and it worked after 3 tries. Not sure what I did wrong the first two times, but it works now. Awesome! I love this message board!

bluebee · Oct 29, 2010

I'm a little confused. This E46 thread calls it a "battery"
- Diamond Key battery replacement

Here's what it says, verbatim:

You CAN replace a battery, but you must have a little patience and some special tools.
Here is what you need:
1) Small jewelers screwdriver (flathead)
2) Razor blade
3) Soldering gun
4) JB weld ($5.00)
5) New battery (Panasonic VL-2020 Lithium Coin Cell battery: $5.00)
6) Super glue ($2.00)

I could not find any place in Seattle to buy that battery, so I found a place online called Mouser Electronics ( www.mouser.com), and got one for $5.00 and $5.00 shipping, so ten bucks for the battery.

Replacement Procedures:

1) Gently pry open the key by forcing the screwdriver in the rear center of the key. You will score the plastic, but the battery sits back there and you are away from the electronics for the remote. My key split open fairly easily, but the edges were rough, so I smoothed them down with the razor blade.
2) Pop out the board inside of the key, you can't miss the battery. You can see the battery has a positive and negative lead soldered to the board. Using your soldering gun, melt off the solder that is holding the leads to the board. The battery will fall off.
3) The leads on the battery I got were similar, but did not line up exactly, so I had to bend one of the leads to fit the hole pattern on the board. You can also pry off the leads on the old battery if you want, they are tacked on, but you can pop them off with the screwdriver. My soldering skills are lacking, so I used a little dab of JB weld to hold the new leads in place.
4) Put the board with the new key back into the key housing. Put a little super glue on the edges of the housing and press the two parts of the housing together until they are secured (Make sure the board and battery are installed correctly!)
5) You have to initialize the key. (This is covered a lot in the forums.) You must do both keys at the same time. I re-initialized the new key, then the old one I had just put the battery in. Both checked out, viola! Extra key now works!

So, 15 minutes later and about $20.00, I have an extra key that is fully functional. If you want to save $200 bucks and have a little time, you can make an old key remote work again, or just use your key manually. Hope this helps someone!

Note: Pictures below are from this thread.

energizedmortal · Nov 2, 2010

i tried reinitializing a spare key i had sitting in a shelf for about a year... it would not activate for more than 600 miles but now seems to have charged back and is working again

bluebee · Dec 19, 2010

As an xref, here are what I gather to be some of the best of the diamond key related threads:

- BMW diamond key opening, charging, recoding, battery replacement & recoding (1) (1) (2) (3) (4)

If you know of better related diamond key threads, let me know so anyone looking in the bestlinks thread can find them in a flash.

BB

bluebee · Oct 11, 2011

In doing the research for someone who didn't, I realized belatedly the bestlinks had plenty on the diamond key but not a good set of references for the square key battery replacement.

So, to increase the incrementalistic value, I added the following just now based on reading the links below ...
- How to replace the square key battery (1) (2) (3)

2001 E39 Key Battery Replacement

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