[IllestBeams94]

Hello fellow e9x's,

I have a problem and i don't know what to do..

My non comfort Access key fob has died a couple months ago, now i know they're suppose to charge while i drive, and i haven't even tried to use it for a couple of months now, but im starting to miss the fact that i cannot open my doors anymore at the simple click of a button. sometimes it use to work, then it didn't, now it doesnt work at all. i did have a second key, but it got lost somehow during hurricane Sandy. anyway, back to the real question(s)

- is there a way to open up the keyfob and change the battery?
- is there a way to buy a used keyfob and reprogram?
- could it possibly be the car thats malfunctioning?

thanks alot !

[hugus311]

if sitting in car can you unlock doors via central locking button? if you cant might be fuses and malfunctioning solenoid that caused a fuse to blow.

Buying a used one will not work as they are like lobsters... once they mate, they mate for life.

fob batts are not replaceable.

[pillbox]

I have the same problem! Here's what I've done so far:

Check if it is the fuse(s) that have blown, causing the doors to unable to be unlocked. Your fuse board is on the firewall, behind your passenger side cubby. There are two 90 degree turn screws that you just turn left to open. There is an orange tool clipped onto the fuse board that you can use to remove the fuses. Be really careful and try not to drop fuses and the tool down inside!

Open your key fob by taking out the manual key, and splitting open the fob with a small flat-head screwdriver, or a utility blade.
ONCE YOU OPEN THE FOB, YOU WILL NEED TO RE-SEAL IT WITH SUPER-GLUE OR EQUIVALENT ADHESIVE (AFTER SANDING DOWN OLD ADHESIVE). KEY FOB WILL STILL WORK WHILE IT IS UN-SEALED AS LONG AS A RUBBER BAND IS HOLDING IT TOGETHER.


These are the solder points that hold down the battery.


This is the battery (Panasonic VL2020)


Order the battery by searching around on google, it will come with the BMW-specific contact points. I recommend using a small soldering pen to remove the old solders and to solder on the new battery.

I'm still waiting for my battery and new housing (current one is beat up) to arrive. Good luck!

[hugus311]

Originally Posted by pillbox

I have the same problem! Here's what I've done so far:

Check if it is the fuse(s) that have blown, causing the doors to unable to be unlocked. Your fuse board is on the firewall, behind your passenger side cubby. There are two 90 degree turn screws that you just turn left to open. There is an orange tool clipped onto the fuse board that you can use to remove the fuses. Be really careful and try not to drop fuses and the tool down inside!

Open your key fob by taking out the manual key, and splitting open the fob with a small flat-head screwdriver, or a utility blade.
ONCE YOU OPEN THE FOB, YOU WILL NEED TO RE-SEAL IT WITH SUPER-GLUE OR EQUIVALENT ADHESIVE (AFTER SANDING DOWN OLD ADHESIVE). KEY FOB WILL STILL WORK WHILE IT IS UN-SEALED AS LONG AS A RUBBER BAND IS HOLDING IT TOGETHER.


These are the solder points that hold down the battery.


This is the battery (Panasonic VL2020)


Order the battery by searching around on google, it will come with the BMW-specific contact points. I recommend using a small soldering pen to remove the old solders and to solder on the new battery.

I'm still waiting for my battery and new housing (current one is beat up) to arrive. Good luck!

i wonder if once you replace battery if you require any programming or it will fire right up?

[pillbox]

Originally Posted by hugus311

i wonder if once you replace battery if you require any programming or it will fire right up?

It needs to be initialized (which for e90 I believe is just sticking it in the car for a few seconds). But don't take my word for it, I will report back with results and a full DIY once my battery arrives!

[PSEE]

A guy here at work recently replaced the battery in my wife's key fob. We did
the procedure because the fob stopped locking/unlocking the doors. With the
new (rechargeable) battery, the fob will start the car (I tried it last night).

That suggests the ID for (the fob) talking to the car is in non-volatile memory.

I did note that the remote lock/unlock still does not function. My wife is going
to drive with this key on the weekend for 45 minutes to see if the battery needs
to charge in order to transmit a signal to lock/unlock the doors.


Consider that when you buy other rechargeable appliances, the first operation
you typically have to perform is to "charge the battery".

[ctuna]

There was a procedure for initialization on ytube
It was for a e46 style fob but it might work on an e90.
I believe the fob will start the car in the slot if the battery is totally dead.

[VMRWheels]

Sometimes you may need to heat up the key fob to break the glue

[pillbox]

Originally Posted by ctuna

There was a procedure for initialization on ytube
It was for a e46 style fob but it might work on an e90.
I believe the fob will start the car in the slot if the battery is totally dead.

Confirmed, my key fob with a dead battery starts the car just fine.

[dborelli]

How often are you supposed to charge your keyfobs? I have one I use all the time, but the second one sits in my closet :-(

[cbad335]

Originally Posted by dborelli

How often are you supposed to charge your keyfobs? I have one I use all the time, but the second one sits in my closet :-(

I believe that is stated in the manual.

[IllestBeams94]

Pillbox, thanks for the write up, nicely done. Good news : got it open desoldered the battery, tested it... Bad news: battery was fully charged (now im clueless)

[pillbox]

Originally Posted by IllestBeams94

Pillbox, thanks for the write up, nicely done. Good news : got it open desoldered the battery, tested it... Bad news: battery was fully charged (now im clueless)

My battery came in today, so I de-soldered the battery and replaced it with a new one. Does the same thing as before! This perhaps means the problem is receiving end?

Here are my symptoms:

• All lock/unlock works with either metal key or central locking button on the dash.
• Key fob does not lock/unlock with any button.
• When pressing a button on the key fob, the car reacts with a "priming" noise, and the start button lights up, as well as the shifter light.

I'm guessing it could be the receiver, but I have no idea how to test this. Looks like I'll have to make the rounds to the dealership

[thaking]

Hi there,

is there any DIY for all procedure (which glue to use...) to open NON-cofort access for BMW keyfob ? I think my battery is not in good condition any more so I need to change it ...

[RogerRamjet]

Originally Posted by PSEE

A guy here at work recently replaced the battery in my wife's key fob. We did the procedure because the fob stopped locking/unlocking the doors. With the new (rechargeable) battery, the fob will start the car (I tried it last night).

That suggests the ID for (the fob) talking to the car is in non-volatile memory.

I did note that the remote lock/unlock still does not function. My wife is going
to drive with this key on the weekend for 45 minutes to see if the battery needs
to charge in order to transmit a signal to lock/unlock the doors.

Consider that when you buy other rechargeable appliances, the first operation
you typically have to perform is to "charge the battery".

Hi PSEE, Did the battery eventually charge up enough to remote lock/unlock again? If not, have you since learned what is required to get it working?

[andy_06xi]

My spare non-CA keyfob stopped working the doors remotely (but would still start the car). I cut it open and desoldered and changed the battery using the recommended procedure above. While the old battery was low on voltage -- the new battery worked no better. Once reglued together, I still couldn't open the doors remotely -- but could still start the car.

I also tried a $50 replacement from e-bay (same frequency). I was hoping it would 'intialize itself' on first usage. No go.

I finally broke down an ordered a new fob from the dealer. Since I already had the metal key part -- the plastic part of the fob was only around $180. This was ordered from NJ using my VIN. The key just worked when I tried it.

[kiel_dafo_kenyg_as]

Check for broken solder joints on the three push buttons. A broken joint may not be visible but you can poke around a bit with a needle or small screwdriver while holding the button down and watch what the car does. Be very careful not to short pins. If you're successful and good in soldering you may resolder or even replace the button(s).
I recommend wearing rubber gloves to prevent damage to electrostatic sensitive devices (ESD)

[dsteinhil]

If your battery is dead from lack of use (that is, not permanently dead) just go for a long road trip and it should recharge (a couple of hours).
Another option is to place it in "On" position in the ignition while the car is hooked up to a trickle charger but not running.
If those options don't work you're back to replacement.

[sebringsc]

i have a 2011 335 without comfort access and the key fob with a rechargable battery.. my key fob starts the car but will not unlock the doors remotely.. I opened it up and the battery is fine ( cheked it with multimeter) so I think the key just needs to be synced or programmed again.. Ive seen it done on the diamond shaped keys but not on mine,.. Suggestions, besides getting a new one?

[mkov608]

Pillbox, thanks for posting. I took my key fob apart with an xacto knife.

After reading that your remote wasn't working after replacing the battery, I devised a way to keep power on the circuit board while replacing the battery.

I put two D cell batteries together and connected wires to the positive and negative terminals, I soldered the other ends to the remote circuit board and then used alligator clips to hold the wires to the board. Then I de-soldered the old battery and soldered in a new one. the remote works perfectly, now I just need to clean up the edges of the fob case and glue it back together. The battery was $9.00 on Ebay. Make sure you order the correct mount.

OBTW, the VL2020 is a lithium ion battery; you can't test it like a normal battery. It may show 3.0 volts when you check it with a multi-meter, but it may not be producing any amperage.

[VTECaddict]

Your picture looks like fob is smoking/burning...

[PTinVT]

Originally Posted by dborelli

How often are you supposed to charge your keyfobs? I have one I use all the time, but the second one sits in my closet :-(

I have 3 fobs (dealer error in my favor) and I rotate them so they each get used one month/sit for two months. I've had them for 8 years and none of them have ever not worked.