E46Fanatics (http://forum.e46fanatics.com/index.php)
-   General E46 Forum (http://forum.e46fanatics.com/forumdisplay.php?f=4)
-   -   Diamond Key Battery Replacement (http://forum.e46fanatics.com/showthread.php?t=481585)

benmuellerb 06-18-2007 10:30 AM

Diamond Key Battery Replacement
Okay, my wife had to buy a new key for her 2001 E46 for $225.00:censor: because the remote in the original key would not charge up no matter what. After searching for all of the forums, I have found there is no real concrete answer about replacing the battery in a remote. Since I had an old one, I figured "what the hell" and I would give it a go. Here is what I found out...
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!

tim330i 06-18-2007 11:04 AM

Awesome, thanks for the details!


Chris C 06-18-2007 12:46 PM

Thank you as well. I know it's only a matter of time before I'll use your write up.

benmuellerb 06-18-2007 02:37 PM

Just a follow up, after reading my post just wanted to clarify that when you are reinserting the battery into the board, it is still best to use the solder to connect the leads to the board, I just used the Jb weld to make sure it was secured as JB weld doesn't conduct electricity, so just remelt the solder that is still on the board to attach the leads. No biggie, just wanted to clarify...sorry.

Sal329 06-18-2007 02:46 PM

Sounds good. I wonder why BMW just didn't make it replaceable like the older models? Guess it is better to sell a $180+ key then a $13 battery.

TKC 06-25-2007 03:44 PM

Thank you benmuellerb! I'll be doing this tonight as long as I can find this battery! I've been going ghetto style with manually locking and unlocking the car for the past couple weeks since the dealer said it was $200+ for the new key.

hammer88 06-25-2007 04:38 PM

Did you mean...

4) Put the board with the new battery 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!)

I got a little confused...

benmuellerb 07-06-2007 01:01 PM

To Hammer 88, yes, you are correct. mine directions were a little off there. sorry about that.

BMWh0r3 07-06-2007 01:11 PM

jeebus....i got a replacement remote key for 130 at sun motors bmw in carlisle/mechanicsburg pa.....you guys are really getting jacked for a new key.

hammer88 07-06-2007 05:32 PM

no prob... i just wanted to make sure other readers didn't get thrown for a loop. on a side note, i made sure i drove with my other key to make sure i wouldn't need to invoke this cool process. hahaha. good job OP.


Originally Posted by benmuellerb (Post 6266131)
To Hammer 88, yes, you are correct. mine directions were a little off there. sorry about that.

silverkw 07-06-2007 06:33 PM


tko200 07-06-2007 07:04 PM

You are correct, i replace my battery i bought it at interstate battery, its a panasonic VL2020 rechargeable, the battery is spot welded to the connector
not soldered when you remove the connector from the battery you wont be able to spot weld it back it requires a spot welding machine very expensive
here is the alternative like the first thread said desolder the old connector with the battery, remove the old battery then solder the new connector with battery to the board, easy fix

BaronOttoMatic 09-01-2007 05:11 AM

This is totally Awesome!

LorENZO http://img.photobucket.com/albums/v6...nanaWrench.gif

Silver325 09-01-2007 08:18 AM

This is outstanding!! I have one dead key and this is the perfect solution. By the way, can you point me to the thread for the initialization procedures for the keys? Thanks for posting this!!

coolusername 09-01-2007 10:50 AM

great write up :thumbup:

wdgiles 09-02-2007 10:26 AM

Quick question - Mouser sells a horizontal and a vertical version of the battery. I'm guessing the horizontal version is the way to go, any suggestions? http://www.mouser.com/search/Refine....RefType=Header

win-by-miles 09-02-2007 10:38 AM

is it a normal battery? or does it have to be a rechargable?

wdgiles 09-02-2007 10:58 AM

it's a lithium, rechargable. I ordered the horizontal version. Paid for hsipping, then checked the map and figured out that the place is only about 30 minutes from where I work....oh well. Better than driving all that way for a $5 battery.

Travis42583 09-11-2007 09:25 PM

Just replaced my battery - it works great.

A couple notes:
1) My key did NOT split apart easily. Maybe the glue was old or something, but I had to work at it for like 10 minutes with a knife and a flathead to get it open. Now, the edges are really rough and the key has visible signs of being opened, but its OK because it actually works now.

2) I did purchase the horizontal version of the battery. As mentioned in prior posts, the leads did not match up to the holes on the circuit board. Unlike other posts, however, I was not able to easily bend them such that they would fit, so I had to use a piece of wire to get the lead the rest of the way to the solder pad. As a precaution, people who are unfamiliar with soldering should get help from a friend who has experience.

Other than that, the process worked great. My key can now consistently open the doors from over 20 yards away - a big improvement over the intermittent close-range behavior I had been dealing with. Thanks benmuellerb.

fmzip 09-12-2007 10:03 AM

You can get them from Digikey also:


All times are GMT -5. The time now is 10:50 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - 2016 performanceIX Inc - privacy policy - terms of use