Porsche App not connecting after 12V failure

[Dr Bob]

Hi All,
Not been on the forum for a while, but needs must.
Well with all the flu going round and Christmas and all that, the car (2022 Taycan turbo) has been driven around 5 mins a week for the last month and so with the sub zero temps in Scotland last night, the 12V battery (and hence the car) was dead, despite lots of charge in the main battery.
Porsche Assistance came out (in less than 20 mins!!!) and got it going and it is now on charge. Problem is I cant get the app to connect to the car any more - which is a pain as I can't precondition the heating.
Any suggestions? Do I need to reboot the car (with the 2 fingers) or is there an easier way to tackle it?
Andy

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[MrJones02]

Also had a dead 12v last week, same circumstances as you, car hadn't had much action the last few weeks.
Anyway, does your PCM show you have LTE connection, or does it show something like this: =/=
Does it still show your name? (so logged in with porsche-ID)
If no connection, perhaps you need to take it out for a spin so it gets into an area with better reception?

 

[Genau]

Problem is I cant get the app to connect to the car any more - which is a pain as I can't precondition the heating.

As a work-around, you can program pre-conditioning schedules etc. in the PCM.

 

[Dr Bob]

Thanks both.
Yes there was a decent LTE connection but not re-connecting.
However, by late evening, 8hrs after the event, it all of a sudden started working again without intervention. All back to normal now so thanks for the help.
Problem sorted.

 

[W1NGE]

Thanks both.
Yes there was a decent LTE connection but not re-connecting.
However, by late evening, 8hrs after the event, it all of a sudden started working again without intervention. All back to normal now so thanks for the help.
Problem sorted.

Sounds about right!

Could be an issue brewing with the 12v battery however as it should not have gone "flat" given it was energised several times in the month and the HV had ample charge.

We have copious amounts of snow in NE Scotland but temps aren't that low considering.

I'd get it checked out when able.

 

[eddieterry]

Not sure which year you have but my 2023 is booked in for an update to the 12 Volt switch software / firmware which they say is for my year and just come out and should sort the problem of low 12 Volt messages etc which has been a problem with mine each winter since I had it (they have in the past done extensive tests and have always maintained no problem with the battery or software) - if it solves the problem I will update.

 

[Jwa1]

Same here, parked for a week and it went flat. I know two other Taycan owners who had the same issue last week. Mine had also downloaded the latest high voltage software update. AA said they have been going out to lots of flat Taycan batteries.

 

[Dr Bob]

Same here, parked for a week and it went flat. I know two other Taycan owners who had the same issue last week. Mine had also downloaded the latest high voltage software update. AA said they have been going out to lots of flat Taycan batteries.

James, that is interesting!
They uploaded the high voltage software in November so perhaps it is something to do with that. I was only parked outside the house and the AA turned up in 20 mins so no hassle. I'll see if happens again.
Andy

 

[anonymouse]

(Repeating from another thread because it may be helpful here)

This time last year the 12V in my previous J1 Taycan went flat after 9 days. The same happened to other owners in several countries as reported on this forum. We had all sorts of hypotheses floating around at the time.

I have just been advised that my J1.2 has an outstanding software update for the 12V battery. The update addresses a problem that under some conditions the 12V battery may incorrectly report its charge status, leading to it going flat if not driven for a long period.

So it seems that although it took them a year (!) Porsche have now identified the root cause.

 

[Seatactony]

This bug has hit my car. Car locked me out with what appeared to be a dead 12v battery late last week after sitting idle for 2 days. Never had any prior issues on this front.

I called my local service department and was advised to call P-roadside assistance. Did so and they indicated that the car needed to be towed in.

Tow service eventually showed up and indicated that they could jump the 12v and that it would recharge off the main battery. Followed their recommendation and, just to play it safe, drove the car for 30 minutes once the process was complete to recharge the 12v. All seemed fine.

For the past two days, however, I’ve gotten a message at startup indicating “12v battery low, please connect to charging equipment."

PCM also seems to be stuck in an update loop: (1) every day I receive a message via the PCM indicating that there is an update available (“Finder – Dynamic content update available”); (2) I download the update and receive a message indicating that the PCM has been updated; and (3) the same message returns the next time I start the car. This morning, the PCM was stuck at the startup screen (“Porsche”) during my entire 30 minute drive to work.

Summary: this has the hallmarks of a software bug introduced by the latest update or relates to the fact that the update needs to be performed in-house at the service department (despite the car apparently believing differently).

Taking the car in next week and will advise. Please let me know if anyone else experiences similar issues.

Thanks

ST

 

[M3Taycan]

What version of PCM software is in your Taycan?

Here is my version from a recent 20K service on January 5, 2026.

 

[prj]

The PCM version has absolutely nothing to do with the 12V battery.

My brand new J1.2 also has the 12V battery sensor recall btw.

 

[M3Taycan]

The PCM version has absolutely nothing to do with the 12V battery.

My brand new J1.2 also has the 12V battery sensor recall btw.

OK. Thanks!

Is this 12V battery sensor recall for only J1.2?

 

[eddieterry]

OK. Thanks!

Is this 12V battery sensor recall for only J1.2?

No I have the 12V battery sensor recall for my 2023.

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