[Komzie54]

Hi all,

I have a 2018 X1 that was stood for about 2 months needing repair. Whilst stood in my driveway, the battery low warnings were on. Now I have been driving it occasionaly that has all gone away and I am left with just the SOS call failure upon start-up and then 'usually' throughout all journeys.

I have noticed that when the SOS call failure is on, I also cannot scroll the instrument cluster using the BC button on indicator switch, nor can I '0.0' the mileage using the button on instrument cluster.

There are occasions when the SOS call failure doesn't illuminate and the BC button works AND I can zero my mileage. This has been usually after about an hour of driving and then restarting (although it went off itself once on the motorway without restarting the car). However the next day even after motorway driving it is back again. And usually for my town driving it never goes away...

What could it be? Surely if its an additional battery (that I am reading about) then that would be charged by now? Afterall even my heated seats and stop/start work.
I don't know if it could be a fuse? But then it is consistent that it usually goes away during a long drive.

All 3 things are definitely linked.

This being said, I have only driven the car a month yet, and only done 1 motorway journey of 70 miles (1.5 hours). Does it need more time?

[mrpingu]

That battery just dies after x number of cycles. If it is after x age it just doesn’t charge up enough anymore.

[Komzie54]

Originally Posted by mrpingu

That battery just dies after x number of cycles. If it is after x age it just doesn’t charge up enough anymore.

Is there any way to know for sure it is that?
Would a fault code appear on a computer?

[mrpingu]

Yes most likely fault code:
B7F343: Backup battery: Before end of life

Not 100% for sure, but pretty good chance. As this is a know failure on BMWs

[Berty]

Hi
I'm having a similar issue on my x2. Why would the bc button stop working when the tcb emergency sos battery needs changing ?

[mrpingu]

Originally Posted by Berty

Hi
I'm having a similar issue on my x2. Why would the bc button stop working when the tcb emergency sos battery needs changing ?

That’s a good question, dont really understand that either. I have no logical explanation

[mrpingu]

Now it's -25C here in Norway the SOS System error has been on for me aswell...

AAAND so the BC button stopped working. I don't know why but these 2 definitely are related. Maybe because the KOMBI displays the error in the right corner as kind of popup and thus disables any other functionality?

[jehill]

The SOS failure (TCU battery) and the BC button are linked on X2 as well. Mine demonstrate exact behavior you are describing. TCU battery replacement is difficult and costly so I decided to code out the error with Bimmercode. Worked perfectly and I got full function of BC button back. You can see details in my posts on F39 section of this forum.

[mrpingu]

Originally Posted by jehill

The SOS failure (TCU battery) and the BC button are linked on X2 as well. Mine demonstrate exact behavior you are describing. TCU battery replacement is difficult and costly so I decided to code out the error with Bimmercode. Worked perfectly and I got full function of BC button back. You can see details in my posts on F39 section of this forum.

Yeah I did the same for now.


In summer I will try to replace the battery myself.
I don't think it's too difficult but just time consuming, there are no videos of our model but I guess it's the same procedure.
Remove D pillar trims; Then partially remove roof liner and hopefully we are able to get to the battery.

Based on your post and others I found out how to calculate those bytes and code out every specific error in KOMBI ECU

[Berty]

Originally Posted by jehill

The SOS failure (TCU battery) and the BC button are linked on X2 as well. Mine demonstrate exact behavior you are describing. TCU battery replacement is difficult and costly so I decided to code out the error with Bimmercode. Worked perfectly and I got full function of BC button back. You can see details in my posts on F39 section of this forum.

This one...

Great info.. good to know it was your first time using it. I need to pluck up the courage...lol

I found this solution by Mark333032 in Bimmerpost, used for a different BMW model. Many thanks.

"Open the Bimmercode app and go to Instrument Cluster/Expert Mode/3301 CC_ID_Sperre/CC_ACTIVIERUNG_5/Custom Value. You should see 'FF' listed in Bytes 0 to 7. Scroll to Byte 5 and change it from FF to F7 and press 'Done'.
Then back out to the 'Instrument Cluster' menu and hit 'Code'. The 'SOS Call System Failure' message is now gone. The only thing the car asked me to do was reset time."

This worked perfectly on my F39 to eliminate the very annoying "Emergency call malfunction" error message on the dashboard. This is most often caused by a dying TCM battery which is located under the shark fin and extremely hard to replace because you need to remove panels and lower the headliner. The replacement battery costs about 65 USD but the BMW dealer charges an additional 400+ USD for service to replace it. Batteries last 3 - 4 years (or less depending on climate) and you will then need to replace again.

This was my first use of Bimmercode but it ended up being easy, only a one byte code change. I used the Vgate iCar Pro Bluetooth OBD2 Code Scanner to connect Bimmercode to my car, about 32 USD on Amazon. Only scary part was the dashboard went black after coding and rebooting the ECU. I waited a couple of minutes, turned the ignition off and back on, and everything came back. Just had to redo the time and date in the menu settings.

[Berty]

As a side note, ive had the battery replaced by my local garage, not sure if he has the necessary software / hardware to reset this particular error on my X2.
The fault remains though, even thought the battery has been replaced.
Does the error need clearing, or should it just clear once the battery has been changed ?