[dmaxdmax]

If you have an "SOS Emergency phone not working" message and a little yellow triangle on cluster that's annoyed you and you'd rather not pay whatever the dealer wants...probably at least an hour...which probably means two...you can do it for $60. (If you have the ability to clear the code--I used Foxwell NT530) If not, you can get one, use whatever software you use, or get a shop to clear the code(s) you'll have.

You need to replace the telematics control unit battery...about $60 online.
Links of relevant pages attached.

If you have a 2016 340i and don't find the telematics control unit in the trunk under the floor, then it's probably in the headliner like mine.

https://www.realoem.com/bmw/enUS/sho...40#84106836777


https://www.newtis.info/tisv2/a/en/f...one/1VnZ7fcS04

When you get to the TCU, I used a short pry to hold the roof down...you don't need to do more than remove the two c-pillars and brake light panel to get to it. There is a small tab on the battery door...use a flathead bit to pry it up...you don't need to unscrew the tiny screws nearby. Battery slips in as it came out...very easy.


https://www.newtis.info/tisv2/a/en/f...ights/HnEF3G0G I cracked the single clip...have an extra...but my e46 door card clip worked...exactly the same except I have to file down the diameter a little with a fine file.

There are also two T-25 screws that need to come out...don't unscrew the brake light. Disconnect it...obviously.

https://www.newtis.info/tisv2/a/en/f...rests/HtPALt6p

It does come off...it'll take a firm wedge against something flat...and remember to yank up in direction of arrow (in TIS) after you get the top two clips off. Again, an extra plastic clip would come in handy.

...and hiding behind the panels, for the record if anyone needs to know what's back there...some pics, hopefully right side up.

[dmaxdmax]

Bumping this for the guy who PM'd me asking for this thread.

[Alxsis]

I’m currently having this problem and my SOS button also doesn’t work. Did yours work fine even with the “malfunction” message? 😔

[dmaxdmax]

Originally Posted by Alxsis

I’m currently having this problem and my SOS button also doesn’t work. Did yours work fine even with the “malfunction” message? 😔

I'm not sure I tested it but I know at some point I pressed the sos button by mistake and got bmw. After driving a while, I believe the accumulator/battery builds up enough power to be okay for a little bit. My light went on and off for a little bit before it failed 100%

[pjkbrit]

Am also having the same problem with my 2018 340. I took out battery and got 8.1 voltage on my tester. Do you guys still think I should just change the battery anyway? Also not easy to find online?!?

[Billfitz]

It's an 8 volt battery. If it tests at 8.1 volts there's no reason to replace it. Chances are if you opened up the case you'd find generic lithium battery cells anyway.

[dmaxdmax]

Originally Posted by Billfitz

It's an 8 volt battery. If it tests at 8.1 volts there's no reason to replace it. Chances are if you opened up the case you'd find generic lithium battery cells anyway.

I know little about electrical stuff, but I know mine would 'flash' the warning and then, during a long drive, would go off. Then on again.

The batteries go bad...so maybe his 8.1V is after a long drive? Not sure how to test amperage...but I got my 'emulator' for $50-60 somewhere online. I suspect FCP euro would have them available now. They didn't when I found mine almost 2 years ago.

[pjkbrit]

Originally Posted by dmaxdmax

I know little about electrical stuff, but I know mine would 'flash' the warning and then, during a long drive, would go off. Then on again.

The batteries go bad...so maybe his 8.1V is after a long drive? Not sure how to test amperage...but I got my 'emulator' for $50-60 somewhere online. I suspect FCP euro would have them available now. They didn't when I found mine almost 2 years ago.

FCP have one that looks the same for a Mini Cooper but the part number isn't the same. Thanks for the response

[Billfitz]

It's a rechargeable battery, so it could be running low on charge between drives. Mine was occasionally flashing on start up last winter, which I attributed to the cold temperatures and my only driving once a week. It didn't do it often enough for me to bother opening it up to change the cells, which I will do if it gets worse this winter.

[pjkbrit]

Originally Posted by Billfitz

It's a rechargeable battery, so it could be running low on charge between drives. Mine was occasionally flashing on start up last winter, which I attributed to the cold temperatures and my only driving once a week. It didn't do it often enough for me to bother opening it up to change the cells, which I will do if it gets worse this winter.

Update; finally bit bullet and went to dealer for a new battery. Was shocked they actually had one in stock… superseded part number of course and $115.00!!
Anyway… I installed it but noticed it only registered 6 volts on my gauge and my ok'd one was at 8.16….(max voltage should be 8.2).
Corrected the fault code and the idiot lights have remained off the past 5 drive cycles so I think it's good for now.
Weird that old battery was still clearly functioning at over 8 volts and suspicious that it failed literally days out of warranty.

[AlmondJayRoM3]

Originally Posted by pjkbrit

Update; finally bit bullet and went to dealer for a new battery. Was shocked they actually had one in stock… superseded part number of course and $115.00!!
Anyway… I installed it but noticed it only registered 6 volts on my gauge and my ok'd one was at 8.16….(max voltage should be 8.2).
Corrected the fault code and the idiot lights have remained off the past 5 drive cycles so I think it's good for now.
Weird that old battery was still clearly functioning at over 8 volts and suspicious that it failed literally days out of warranty.

Glad to hear the problem is fixed. As to the voltage thing, keep in mind that batteries can read a good voltage and still be bad. One common issue is that a cell develops a high internal resistance. In this case putting a load on the battery causes the voltage to quickly drop resulting in the issues you were having.

[bobbba]

I followed this YouTube video which talked through fixing it. Took me about 20 mins and now all good:

[Mikael335i]

Hello Guys,
I have the same issue but on a 335i F30 (manufactured on June 2023).
Do you think that the battery is located on the same location than a 340i F30 LCI ?
(It seems to be the case following what I found on ETK website)

Does someone will have the possibility to check if the right P/N for the battery is 84109361678 ?

The dealer asked me 440€ for its replacement, I prefer do it by myself.

Thank you very much for your feedback.

[joesid]

Originally Posted by Mikael335i

Hello Guys,
I have the same issue but on a 335i F30 (manufactured on June 2023).
Do you think that the battery is located on the same location than a 340i F30 LCI ?
(It seems to be the case following what I found on ETK website)

Does someone will have the possibility to check if the right P/N for the battery is 84109361678 ?

The dealer asked me 440€ for its replacement, I prefer do it by myself.

Thank you very much for your feedback.

Yours *should* be below the trunk floor directly behind the rear seats. Fold down the rear seats and flip up the truck carpet while inside the car. It should be under there, if not it's up in the roof.

[YASBBYM3]

Originally Posted by Mikael335i

Hello Guys,
I have the same issue but on a 335i F30 (manufactured on June 2023).
Do you think that the battery is located on the same location than a 340i F30 LCI ?
(It seems to be the case following what I found on ETK website)

Does someone will have the possibility to check if the right P/N for the battery is 84109361678 ?

The dealer asked me 440€ for its replacement, I prefer do it by myself.

Thank you very much for your feedback.

As noted above, your TCB should be behind rear seat in trunk.

The part number you have is wrong. Should be 84109297787

https://www.realoem.com/bmw/enUS/sho...38#84109297787

[Mikael335i]

Originally Posted by joesid

Yours *should* be below the trunk floor directly behind the rear seats. Fold down the rear seats and flip up the truck carpet while inside the car. It should be under there, if not it's up in the roof.

Thank you for your reply.
I'm going to check its location in the coming and I will let you know.

[Mikael335i]

Originally Posted by YASBBYM3

As noted above, your TCB should be behind rear seat in trunk.

The part number you have is wrong. Should be 84109297787

https://www.realoem.com/bmw/enUS/sho...38#84109297787

Thank you for sharing the correct part number.
I will check in the coming days the excal location of this battery for my car and I will let you know.

[Mikael335i]

To keep you informed; I have checked below the trunk floor and I found a battery.
And its part number is 84109297787. (=related to telematic)

On top of this, I have also remove the plastic cover of the 3rd brake light and I have found a battery as well. (=related to SOS function)

Thank you again for your help guys

[rambalu80]

Does anyone know the battery part number for a US model, 2016 BMW 340i with Navigation? I searched for "84102447710" on my local dealer's website and based on my VIN, I get a message that "84102447710" does not fit my car.

My car is a July 2015 build, Type Code 8B33.

[rambalu80]

Originally Posted by rambalu80

Does anyone know the battery part number for a US model, 2016 BMW 340i with Navigation? I searched for "84102447710" on my local dealer's website and based on my VIN, I get a message that "84102447710" does not fit my car.

My car is a July 2015 build, Type Code 8B33.

Answering my own question...the above listed part number worked for my 07/15 build 2016 340i.

Originally Posted by murrayjestin

Did yours work fine even with the “malfunction” message? ��

snaptube vidmate

Yes, the "malfunction message" was intermittent, on sometimes disabling BC button functionality and gone at other times, with BC working as normal. It was annoying and frequent enough for me to replace the battery. I did not perform a reset but message was gone after the battery replacement and has stayed off for 2 days and 200+ miles.

[SJ94]

Originally Posted by dmaxdmax

If you have an "SOS Emergency phone not working" message and a little yellow triangle on cluster that's annoyed you and you'd rather not pay whatever the dealer wants...probably at least an hour...which probably means two...you can do it for $60. (If you have the ability to clear the code—I used Foxwell NT530) If not, you can get one, use whatever software you use, or get a shop to clear the code(s) you'll have.

You need to replace the telematics control unit battery...about $60 online.
Links of relevant pages attached.

If you have a 2016 340i and don't find the telematics control unit in the trunk under the floor, then it's probably in the headliner like mine.

https://www.realoem.com/bmw/enUS/showparts?id=8B73-USA-02-2016-F30N-BMW-340iX&diagId=84_1140#84106836777


https://www.newtis.info/tisv2/a/en/f30-340i-xdrive-lim/repair-manuals/84-communication-systems/84-10-combox-tcb-usb-hub-telephone/1VnZ7fcS04

When you get to the TCU, I used a short pry to hold the roof down...you don't need to do more than remove the two c-pillars and brake light panel to get to it. There is a small tab on the battery door...use a flathead bit to pry it up...you don't need to unscrew the tiny screws nearby. Battery slips in as it came out...very easy.


https://www.newtis.info/tisv2/a/en/f30-340i-xdrive-lim/repair-manuals/63-lights/63-25-brake-lights/HnEF3G0G I cracked the single clip...have an extra...but my e46 door card clip worked...exactly the same except I have to file down the diameter a little with a fine file.

There are also two [...]

Hi mate. I’ve had this issue come up and ordered the battery. I don’t quite understand how I remove the headliner? Would you be able to help?

[KPAXM77]

Hi Everyone, New here, Can anyone tell me where the TCU location is on the F46 2 series Gran tourer 2018 Xdrive? My display is hogged by the error message since 6 months and no mileage or driving data available. BMW is asking for £600 for the battery change. Thanks in advance