Key FOB is Dead

[ejm3]

One of my key fobs has been rarely used and now will not lock or unlock the car (no comfort-access).
It will start the car if I insert the fob but it doesn't appear to charge.

Do I need a new fob or is there a battery that can be replaced?

As I understand it the fob battery charges while its inserted in the car and running so that leads me to believe its not just a normal fob battery.

[mkeiser]

[BMWCCA1]

Originally Posted by mkeiser

The OP said NO comfort access, so no pancake battery under the cover—and not removable battery cover. Many kluge repairs over the years. Try Google.

[Tuxedo]

Originally Posted by ejm3

One of my key fobs has been rarely used and now will not lock or unlock the car (no comfort-access).
It will start the car if I insert the fob but it doesn't appear to charge.

Do I need a new fob or is there a battery that can be replaced?

As I understand it the fob battery charges while its inserted in the car and running so that leads me to believe its not just a normal fob battery.

the video above is for a comfort access fob, if you have a solid key fob and no back panel the only way for a charge is pop it in the car and charges while driving. If it no longer charges buying a new one is the best way, grab registration and head to BMW parts. I have seen vids on replacing the battery on the fob for non comfort however success wasn't assured.

[ejm3]

I don't have CA but my fob looks like that.

[Fishee]

Originally Posted by ejm3

One of my key fobs has been rarely used and now will not lock or unlock the car (no comfort-access).
It will start the car if I insert the fob but it doesn't appear to charge.

Do I need a new fob or is there a battery that can be replaced?

As I understand it the fob battery charges while its inserted in the car and running so that leads me to believe its not just a normal fob battery.

The rechargeable battery may be toast.
I would try charging it while driving, maybe for 30+ minutes.
If that doesn't work, may be time for a new remote.

[BMWCCA1]

Originally Posted by ejm3

I don't have CA but my fob looks like that.

They all look alike, but do you have a removable cover on the back of your remote? If you're sure you don't have C/A then you shouldn't have a remote with a battery cover on its back. If you're not sure, post your VIN and we'll let you know.

[ResinThirteen]

Originally Posted by ejm3

One of my key fobs has been rarely used and now will not lock or unlock the car (no comfort-access).
It will start the car if I insert the fob but it doesn't appear to charge.

Do I need a new fob or is there a battery that can be replaced?

As I understand it the fob battery charges while its inserted in the car and running so that leads me to believe its not just a normal fob battery.

Lots of videos online, but basically you have to heat up and then split the casing to get to the battery, then desolder the old battery before soldering in a replacement.

I have the exact same issue on my second key and planning on trying it myself once I track down a replacement battery and someone with a soldering iron.

[ejm3]

Originally Posted by BMWCCA1

They all look alike, but do you have a removable cover on the back of your remote? If you're sure you don't have C/A then you shouldn't have a remote with a battery cover on its back. If you're not sure, post your VIN and we'll let you know.

Yeah I took a look yesterday and and of course it does not have a removable battery cover

I'm not sure I want to crack it open and try to replace it.

[Lester]

You will have to go to your dealer, and buy a new one. It will have to be coded into the car's computer. Up to 10 key fobs can be coded.

[jdt10768]

soldering batteries: fun AND dangerous!
just go pay The Man . . .

[Thunderguts]

It's not THAT hard to replace the battery. I did it on both my fobs and they're still working just fine 3 years later.

You need a Panasonic VL2020, but you'll notice that the contacts don't match up correctly. Just solder a small jumper wire to the contact and Bob's your uncle.

You can even get knockoff fobs pretty cheaply. Just transfer your circuit board to the new fob and you'll have an entirely new remote.

[ResinThirteen]

Originally Posted by Thunderguts

It's not THAT hard to replace the battery. I did it on both my fobs and they're still working just fine 3 years later.

You need a Panasonic VL2020, but you'll notice that the contacts don't match up correctly. Just solder a small jumper wire to the contact and Bob's your uncle.

You can even get knockoff fobs pretty cheaply. Just transfer your circuit board to the new fob and you'll have an entirely new remote.

Yeah, I have no issues trying the battery change. Worst case I’m left with a fob that still can’t unlock the car.

Or, you know…just retrofit comfort access…which I might be doing. 😳

[Lester]

May the force be with you. You'll need new FOBS, ignition switch, receiver/antennae, door handles, locks, covers, actuators etc. Big job. Some of the wiring harness may not be there.

[Wazowski]

Same as other posters, my 14 year old second key did not get enough use and would only start the car. Replacing the sealed battery was actually quite easy.
Order a pair of batteries and black “moldable glue”. No need to heat, just carefully cut open with a razor blade.
When soldering to release the old battery and install the new, I covered the circuit board with painters tape to avoid unintentional short circuits. Works like a charm. $30 all in with glue and 2 batteries. Will definitely do my primary key when it dies.

[ResinThirteen]

Originally Posted by Wazowski

Same as other posters, my 14 year old second key did not get enough use and would only start the car. Replacing the sealed battery was actually quite easy.
Order a pair of batteries and black “moldable glue”. No need to heat, just carefully cut open with a razor blade.
When soldering to release the old battery and install the new, I covered the circuit board with painters tape to avoid unintentional short circuits. Works like a charm. $30 all in with glue and 2 batteries. Will definitely do my primary key when it dies.

Very nicely done! Now that you’ve done it, so you like the performance of the moldeable glue? I was thinking of using an epoxy or something like that made specifically for plastic, but I’m not familiar with the stuff you used. I’ll have to check it out.

[Lester]

Check this out.

(2 Pack) Remote Key Fob Battery for BMW Remote Smart Shell Smart VL2020 (2006-2014) 1 3 5 6 Series, M3 M5 M6 X5, X6, Z4 E39 E46 E60 KR55WK49123 KR55WK49127 with Instructions (Without Comfort Access) https://a.co/d/8YNFv5y

[Wazowski]

Be sure to check the number of connections on the battery that your fob has. My 2008 has the old two prong battery. I opened mine up before I ordered to confirm. Regarding using the moldable glue, it comes in 3 foiled seal packs. You only use a small amount from one packet. Keep something heavy on the key (or clamp) while curing for 24 hours, being careful not to keep any of the buttons depressed causing your new battery to drain.

[Blau]

Just went through this. Amazon had a cheap soldering iron, the battery in it's correct orientation (the posts need to be 90⁰ apart), and they had a OE looking key surround that snaps together and permanently stays closed so it won't fall apart. About $60 later I had a key. Took ten or so minutes.

Don't go buy the key if you can afford the 10 min to DIY and have a great looking and feeling OE style key that works 100% as well as the $350+ one you're going to get at the dealership.

To the guy worried about solder and the battery. You put a dab of the solder on the board and then slide the battery post into the hole. The battery itself never touches the solder. It's very easy to do this and not mess it up.

I've included the links that helped me finish this job.

Repair video - https://youtu.be/-d0TJ-PEbRs

key plastic - https://a.co/d/4uOJjpc

battery - https://a.co/d/gw75eAA

soldering iron - https://a.co/d/0kA9EDn

[jdt10768]

Good info - This should prob be placed as a sticky under DIY / electronics

[Rwhelton]

Does the battery need to be rechargeable that goes back the fob with solder?

[Lester]

Yes, you need a Panasonic VL2020, check on Amazon they have a case and battery for $40.