I found this issue using OBD:

Backup Battery – Service Life Critical
Manufacturer-Specific Fault Code: B1916F4

I tried to clear the fault, but it comes back as active after rescanning.

Has anyone experienced the same issue?
How can I fix it?

Hi, welcome.

Sorry but the question might be quick but my answer isn't. If you want quick only go to very bottom of this post.

Do you have a back up battery - and what is a back up battery, does the car have two 12v batteries or does it mean the alarm battery? (or other, see below)

First thing I would do if the car only has one 12v battery (or even if not) is to fully recharge it with an appropriate battery charger maintainer following the car's 'Owner's Manual' and instructions for the charger maintainer. I would use a lower (slower) amp charger maintainer so it may may take very many hours to recharge the battery to full but this can be done in one or two or more sessions if there are time restrictions.

If you only have the one 12v battery - if the battery is allowed to go too low in state of charge the computers don't like it and can throw up all sorts of unexpected warning lights and messages and error codes and car issues. The battery may be good enough to have the headlights seem bright enough and easily start the engine but still be too low for the computers.

The first signs of low state of charge for the battery is the stop/start not operating when it should and just driving the car to charge the battery sometimes is not enough to charge it enough.

12v batteries like 20c weather temperature and self-discharge twice as much at 30c (and twice as much again at 40c).

In hot weather the air-con is used more, the air-con uses a lot of electricity (as does steering).

The 12v car battery is one of the most oversold car parts with premature change when often proper full recharging would have been sufficient for at least some more reliable battery life, possibly much more.

This code, I don't know might also relate to the alarm battery(?) but again I don't know and it's hot (warm to some) at the moment.

What scanner are you using, is it programmed for your model and (part) year or VIN, was the program check to be fully up to date before use, was the car's 12v battery at a reasonable state of charge (and if appropriate same for scanner)?

Google search brought up the following that look like a back up battery for something not all car electronics are the finest so I would still consider the heat as a possible factor, at one time VW fitted engine starter relays that didn't like the cold. - https://www.google.com/search?q=VW+B1916F4&rlz=1C1VDKB_en-GBGB1100GB1103&oq=VW+B1916F4&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTgzMDJqMGoxNagCA7ACAQ&sourceid=chrome&ie=UTF-8

HTH.

This is a backup battery in the OCU unit. According to the workshop manual, the main battery should be charged for about two hours with the ignition on. Then run the diagnostics again and if the error persists, replace the battery in the OCU unit.

From quick online search of OCU -

?

"What is the OCU(Online Connectivity Unit)

The OCU stands for Online Connectivity Unit

• It's a telematics device that LGE is developing for the Volkswagen vehicles

• It is a small box installed deep inside passenger cars, and in charge of wireless communications in. GSM, WCDMA and LTE network

• It provides voice and data call functions and various online services requested by VW"

?

Edited 1 July, 20251 Jul by nta16

nta16 accurate description. In Scala located above the fuses.

@b0rger did you get a resolve to this or more information?

@nta16 The solution, according to the workshop manual and today's words from a technician at a Škoda car service, is this: With the ignition on, let the vehicle battery charge for two hours.

15 minutes ago, richi661 said:

@nta16 The solution, according to the workshop manual and today's words from a technician at a Škoda car service, is this: With the ignition on, let the vehicle battery charge for two hours.

Yeap, I saw that but wondered if the OP did. I wasn't doubting the information. More electronics to go wrong, how wonderful, add it to the ever growing list. 😄

Edited 4 July, 20254 Jul by nta16

I just saw that error on my car lltodsy when I was testing obd app on AA. What was odd is that I took my car with odd time, as it was 5:40 and I was there around 18 o'clock. However, at the time I wasn't thinking much about it. I can only assume they did something with the 12v battery like charged it. However, after driving the car for 30 minuts the error is still there and it's a persistent one. I plan to drop next week back to the official service where I did a maintennace a week ago and ask them about it. However, the best results I get when I tell them what to do ;) Do you any hint for me?

My battery was recharged at the service center at the beginning of July. Today it was found that the error persists. So, I will have to replace the backup battery in the unit. The battery has the number 3G0 915 089.

3 minutes ago, richi661 said:

My battery was recharged at the service center at the beginning of July. Today it was found that the error persists. So, I will have to replace the backup battery in the unit. The battery has the number 3G0 915 089.

Thanks for the feedback! As my car is still under extended warranty till June 2026, I'll try to replace it under warranty. I'll let you know how it went.

On 12/09/2025 at 22:51, FnLn said:

I just saw that error on my car lltodsy when I was testing obd app on AA. What was odd is that I took my car with odd time, as it was 5:40 and I was there around 18 o'clock. However, at the time I wasn't thinking much about it. I can only assume they did something with the 12v battery like charged it. Hunder owever, after driving the car for 30 minuts the error is still there and it's a persistent one. I plan to drop next week back to the official service where I did a maintennace a week ago and ask them about it. However, the best results I get when I tell them what to do ;) Do you any hint for me?

Official service has installed a replacement battery for OCU (low version, meaning no updates possible/available) unit for free having still car warranty.

Edited 1 October, 20251 Oct by FnLn

If you have ObdEleven

It is possible to reset the learned values for the battery (and thus the rSoH) without having to install a new battery (cost approx. €350-500).

It is suspected that VW Group does nothing different in the TPI.

Instructions for OBD11 Pro:

1. Open the hood and leave the driver's door open
2. Connect the OBD11 dongle to the OBD port in the driver's side footwell + start the software.
3. Select control unit 75 / Telematic
4. Check error code: B1916F2 / Backup Battery critical
5. Live data: If Backup_Battery_rSoH <= 50%, then the SOS message is active on the display and the LED is red.
6. Basic settings: Activate the emergency call battery history reset (press the green checkmark). OBD11 may not provide any confirmation of the reset. Simply go back and complete the remaining steps.
7. Error memory: Delete error B1916F2 (press and hold the trash can icon)
8. Live data: Request Backup_Battery_rSoH: 100%
9. Ignition off / Ignition on (Warning message is now gone and the status is green again)

Enyoj ... 

It would be good if there was an option of less than 100% as the battery has had 4-5 years use, whether something like a VCDS would be better for this I don't know.

Hi, I had used this method and reset battery stats. Does car ECU measure battery stats like capacity and voltage, or this battery life meter is only based on time that has elapsed since car manufacture year ? I had bought new battery but it is quite hard to dissasemble the eCall module. After crash eCall unit can use main car battery to make a call ? It seems to be stupid is only power of eCall module is this litte backup battery. Anyone now more about it ?

On 03/07/2025 at 18:55, richi661 said:

nta16 accurate description. In Scala located above the fuses.

Do you know what exactly should I dissassemble to replace battery ? As far I know eCall module is real deep behind the fuses on the left side near lights switch. Is there clips or screws to take of ? Is there some kind of manual that could help with battery replacement ?

2 hours ago, radoszczak said:

Does car ECU measure battery stats like capacity and voltage, or this battery life meter is only based on time that has elapsed since car manufacture year ?

I'd be surprised if it isn't capacity and voltage type measurements as it's recharged off the main 12v battery - but I don't know for sure.

I've no idea how in depth OBDEleven Pro goes with details but VCDS has rediculous amouts of details available so perhaps see if someone with VCDS in your area can help you. - https://www.briskoda.net/forums/topic/262215-list-of-vcds-owners-previously-known-as-vag-com-vcp-owners/#comment-3091029

And/or look in the 'Diagnostics & VCDS' forum as there are some Briskoda members that know lots about coding and computer set ups. - https://www.briskoda.net/forums/forum/23-diagnostics-amp-vcds/

HTH.

Thank you for your response. It May help but for now I will just use car without battery replacement. As far I know capacity of li-ion based batteries can last even 10 years with 70-80%. Is it possible to reset battery stats from 50% to 100% it seems car ecu aproximate battery Health only based of lifespan. If ecu reads capasity and voltage ,errors should be pernament, and not able to reset. There is shadow of idea that red nofitication shows after about 5 years and force user to visit workshop to replace battery or just reset stats. In My country yearly car control needs no red indicators. I just looking for answer, is it safe to ride with 5 y Old battery for next years. I dont want to replace good battery for new one.

Two things I would rule out are that trhey may be a fault in ther haedware or software to the OCU or something it relates to (infotainment? or elsewhere) and secondly that yes perhaps VW do have a forced (false) "end of life" type con programmed in related to time but those are only possibilities.

As the battery charges from the 12v battery I would guess, don't know, that there must be some kind of measuring of this.

I don't know if this post with link tin that post to general info about the OCU and an example phone of one helps you at all generally but here it is. - https://www.briskoda.net/forums/topic/523358-is-this-navigation-symbol-normal/#findComment-5850217

The following gives a shout out to @Cairus as he may well be able to give answers to your last post.

HTH.

The OCU's backup battery isn't charging. If you get an error message, good luck replacing it...

3 hours ago, Cairus said:

The OCU's backup battery isn't charging. If you get an error message, good luck replacing it...

Do you have more pics of dissasemle of plastics to get to the eCall module ?

This was Scala

47 minutes ago, Cairus said:

This was Scala

I have scala 2021 and the same issue

This

Thank you. Is left plastic bezel that is shown after door open, is on plastic clips or screws ?