key fob kaput
 

Hello all, not tried the 'spare' but key that I have had since got car gave up ghost....managed to lock it but it did not unlock with key fob...had to manulaly unlock then manually lock....stuck key in fridge and after 10mins tried again and key works..so battery? how feasible is it to replace the battery? tad worried about taking knife to it as did this on wifes e46 key and destroyed it a while back....plus what battery is needed?any ideas much appreciated

Not just the battery but the switches and solder joints fail.

Best upgrade I did in the six years I had my e53 was getting a factory replacement key! Bite the bullet and get a real key. You can use the original as an emergency spare.

ta for quick reply....I got a spare but need to try it...and if all ok...then thinking of attacking the flat one

There are videos on how to replace the soldered in battery. I did with both my original keys as well as reflow the bad solder joints. I got working keys out of the process but they didn't work great and after a couple years didn't at all. The weak signal made it seem like the car receiving antenna was failing but when I finally got a new factory key out worked from as block away.

If you have one solid working key by all means look into cutting the non working one open to replace the battery if you have decent soldering equipment and skill.

My plan was to refurbish my failed key once again after I bought a factory key. Car was took out by a deer never got the chance.

Hmmm... my factory new key doesn't work that far away. I gotta get about 25 feet from it before it'll beep.

For me the FZV antenna failed intermittently at first, and then finally stopped working. To my knowledge there is no way to distinguish between a failed battery and a failed FZV. Even using the PA Soft scanner it couldn't tell that the FZV was bad, it just didn't register the key press signal and couldn't reinitialize the keys. (If you can't initialize a brand new key you would know that the FZV would be bad, albeit after you've already spent the money on a new key.)



There's a guy that rebuilds diamond keys as well, though I wouldn't argue with just biting the bullet and buying a new one.



Just another one of the fun and exciting ways these cars break. Fun and exciting for people who like to fix them, not so much for people who just like their cars to work.

If you can find my write up on key I show how to measure the voltage using a couple pins though the rubber button.

I’ll look for pictures but you can confirm voltage before and during button press

I replaced the battery in my non-working fob. It was pretty easy. Works now.

dunno what happened but today is working and even from a reasonable distance and have the spare too just as old that works too....i think i can find a place to clone working key in meantime and also order the vl2020 after opening 'old' key to see which pins it has

Yup indeed no time to be dabbling alas....

https://www.icloud.com/sharedalbum/#B0Z5qXGF1qFCno

Found the photo album. It shows exactly where to poke though the button edges to measure the battery and internals etc.

Dear all, has ANYONE had this issue? The day my keyfob would not play I was parked next to Aluminum structure that houses the buildings AC backup power diesel generator (generator not in use at time).

Since leaving the place the key function was fine

However I parked there next to it again and low and behold same thing, keyfob not working, is it a coincidence or is the aluminum enclosure somehow affecting the rf of the fob....nuts totally nuts

I have had radio interference of numerous kinds cause key fob problems with numerous cars over the years.

ok cheers this is a first for me....weird thing is at home i can unlock it from inside the house as it is parked on the street and our property is fenced off with aluminum panels as wide as your hand roughly... anyway x5 is starting to display the e46 problems with the plastic rubber trim on windscreen and in engine bay specifically near the grill air intake that hugs the trunk when closed, it has just crumbled away...sort of saved it with alu foil tape but that aint gonna create a good seal...

Hi my friend
It's about time you replace your keyfob 😁
https://drive.google.com/file/d/1FyG...w?usp=drivesdk

Hey Merry Christmas! hope all well, believe it or not(and it might no last mind you) put the key on an iphone wireless charger bought for the wife, and after a couple of hours on charge it actually worked....but if battery is on last legs its on last legs, like the main battery that on christmas eve i thought best to change after 7 years (not long i know) but hey didnt want any sudden loss of the car over christmas period....anyhow paid same price today as i did say years ago as they made a mistake but honoured their word on price they had quoted me....

A Magsafe or Qi wireless charge pad will work on these fobs? If so, good to know.

I got mine working again recently by re-pairing it to my X5; I assumed like a dummy that the battery was toast but I went to a specialty battery place that had a remote signal tester and it put out a strong signal, so I was definitely wrong about that.

hmmm key sort of went belly up again, seems the charge only have the key a temporary boost, so may leave it on charge longer than couple of hours i did before

I leave my only OEM key on the Philips Sonicare toothbrush charger 24/7/365, that I bought on Amazon just for that purpose.

The key fob went dead on the second day after I got the X5, so I bought the inductive charger immediately.

However, the key's battery would only hold a charge for a very short time, so I then purchased a replacement VL2020 battery and installed it. It solved the problem.

Since I seldom drive the X, I put the key on the Sonicare charger as soon as I return to my house; I haven't had problems until recently (intermittent ignition/EWS problem) with the key, but got a new Valet key (at a dealership) for the ignition, and have a "remote only" fob (bought as such on eBay, at the same time as I replaced the OEM key battery) to use for locking/unlocking the door.

Now, the batteries in the OEM key (rechargeable), and in the "remote only" fob (uncut blade and non-rechargeable battery sealed inside) are both 4.75 years old (or more), and I'm preparing to cut open both, and put in new batteries.

If the battery in the eBay key isn't replaceable, I can buy another fob from the same seller, and it'll be good for another few years.

I have a new shell with the blade already cut to my X5's pattern already, and a new VL2020 battery, too, standing by, so I'm about to open up the shell of the OEM key and transfer the circuit board and RFID chip into the new key shell, after I replace the battery and resolder the wire trace I had to resolder last time. If I screw up the board, at least I have a back up key and fob.

My X5 is having fuel delivery problems at this time, and is going to be idle for awhile as I gather new parts and tools to diagnose and repair it, so I have time to repair my main key.

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Merry Christmas, thanks for detailed feedback, I have 2 oem keys, daily user was playing up at some point not remote locking, so thought i find the other 'newer' less used spare, thats when i found it was just doing 0 apart from start car and unlock it door lock manually....really am worried about slicing em open to put in another battery, did it on wifes e46 and went through all resistors, lucky she had a second key

I'm hesitant to cut open my only OEM key again, since I cut loose a wire trace the first time, then had to cut it open again to resolder.

This time, I have a specialty Dremel cut-off wheel (instead of a utility knife), and a "helping hands" device (with magnifying glass) to hold it and help me SEE what I'm doing.
Plus, I got a new pair of trifocal glasses yesterday (my first new ones since 2014), so that'll help, too.

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Brave

The battery will die from non use. It charges from being in the ignition switch. Sadly you likely destroyed the battery in the unused key from not using it.

There was a guy would replace the battery for $65 if you didn't try to open yourself. Might still exist.

My batteries were about 15 yr old when I replaced them. They were still ok at that point; the circuit board had broken solder joints. I reflowed the solder on both boards and they both worked like a champ for a couple years. I lost one key on a road trip so i eventually bought a new key and then was ok with surgery on the old key. That Became the emergency key anyhow and the new key worked as remote from at least 5x as far away so i was thrilled i bought the factory key and recommend to anybody with m an old diamond key !

My new x5 and wife's F10 both use normal coin cells you just replace when dead. Not sure what possessed bmw to use rechargeable batteries making keys "throw away".


–awr–

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Confirm you do/n't have voltage and buttons work before disassembly. My posts on the topic show exactly where to poke needles to measure voltage and if you press each button you can see the voltage drop if the click switch inside is working. (you can also charge via the pins: i recommend 20mA up to 3.3v).

If the buttons all work but remote function doesn't, use a remote tester found where they sell batteries (my local Home Depot has one) to test if key is sending a signal and if so then re-sync key.

I managed to cut a trace but not with the Dremel: a drill bit. I drilled through to add two cute little M2.5 Allen head screws to hold the keys closed and got too close to the traces on one of the four holes.


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the problem with my OEM diamond key isn't the battery
 

My OEM key fob has no problems with remote functions, but with intermittent EWS faults; I'm wondering if my recent no crank-no start problems might come from the damaged circuit board inside. I cut it open for the first time, to change the (at that time) original 20 year-old battery, and cut too deeply with the utility knife. I glued it back together BEFORE I tested it, regretfully, and had to cut it open again, damaging the circuit board even more.

The OEM case/shell is a mess, and that's why I bought a new aftermarket case w/precut blade awhile back, knowing that it was needed for the next repair. Might as well put in a fresh VL2020 battery, too.This time, i'm only going to lightly glue the case together (if the tabs don't hold it shut, and put a silicon sleeve over it, just in case it opens up by itself.

If & when I get the X back on the road, I'm planning to get a new diamond key...after years of worrying "when will my key fail?"....

Get a new key to give yourself the freedom to fix the old one. Good plan to move the guts over to a clean shell


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That's why I bought the Valet key, first, as a fail-safe measure, while my main expenditures are focused on fixing the fuel delivery system (the fuel pump went out, replaced it, went from lean codes to rich codes, started stumbling on turns).... Buying parts to re-do it all from scratch, including new tools.

It's not the best time of year for diagnostics/repairs, with five vehicles needing inspection from August-January, seasonal spending, property taxes in Jan., new glasses just now, new phone (bought outright from Amazon, for the wife), and me going to an out-of network ortho specialist next week, it all adds up. A new OEM key is way down my must-have list right now. I'm hoping that I can fix whatever might be wrong with the original key.

You already have the "new key" that makes it safe to open up the old remote key.


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I was able to bring 2 key fobs back to life by charging them on a sonicare toothbrush charger as mentioned earlier in this post. An apple watch charger seems to work too.

I brought one back by replacing the battery.

Anyone wanna recommend a battery replacement service? I know I'd f it up if I tried.

https://fasterautokeys.com/products/...cement-service

Haven't used this but I'd hire them


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I like how they say their service is a fraction of the cost of a new key.

I guess 1/2 is a fraction... :bustingup

5/4 is also a fraction


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Thanks, Andrew. I'm wondering why the new key would need to be reprogrammed, if it has the guts of the original one? (including the chip for EWS, I'm guessing)

Still on my original battery on one of my keys for my 04. The other went through the laundry and died.

key fob kaput
 

The programming they mention is pairing to the car for the remote function to work.

They move the guts to a new key and swap in a fresh battery.

This will usually disrupt the pairing.

Does the laundered one still start the car? If so perfect candidate for refurbish.

I'm not sure if they move the EWS chip over to a new board or just moved the whole board and reflow the solder or what.

Thanks for the response, Andrew.

I tried to replace the battery on that one and it didn't work. My soldering skills aren't the best though.

About six years ago, I got a complete cut key and one uncut one from China something like $30 each. I programmed the remote function, but they have yet to be paired with EWS. I bought the cheapo programming box back then too, but haven't used it since one of the original keys is still soldiering on :thumbup: