Is this the dreaded 12v battery issue?

[KensingtonPark]

Not sure if this hypothesis would care whether the car was locked or not...

Neither am I. However, one of the things that I have noted is that people who need to "reboot" the PCM have reported turning off the car with the Start button and locking the doors. My hypothesis is simply that this is roughly like the difference between "sleep" and "shutdown" on a laptop, meaning that more things are shut down with this process. If so, then it's possible that in this mode the systems that do not totally shut down "wake up" in addition to the things that Porsche is expecting to wake up. Since Porsche do not expect that to happen, the "go back to sleep" commands that are already in place do not instruct those systems to do so and they drain the battery.

It is entirely possible that this is a bunch of crap, that my system for avoiding this is totally not doing anything, and I have just been lucky. Who knows? Not me and not apparently Porsche.

P.S. I also store my keys in a Faraday cage. When I pull the key out of the container, sometimes the car detects the key and interprets this as an approach and unlocks the cars. I know this happens because my mirrors fold back to the ready position. More weirdness.

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[evanevery]

Neither am I. However, one of the things that I have noted is that people who need to "reboot" the PCM have reported turning off the car with the Start button and locking the doors. My hypothesis is simply that this is roughly like the difference between "sleep" and "shutdown" on a laptop, meaning that more things are shut down with this process. If so, then it's possible that in this mode the systems that do not totally shut down "wake up" in addition to the things that Porsche is expecting to wake up. Since Porsche do not expect that to happen, the "go back to sleep" commands that are already in place do not instruct those systems to do so and they drain the battery.

It is entirely possible that this is a bunch of crap, that my system for avoiding this is totally not doing anything, and I have just been lucky. Who knows? Not me and not apparently Porsche.

P.S. I also store my keys in a Faraday cage. When I pull the key out of the container, sometimes the car detects the key and interprets this as an approach and unlocks the cars. I know this happens because my mirrors fold back to the ready position. More weirdness.

I would be the very last person to try and guess what Porsche was thinking when they wrote much of the software for this car.

Despite your laptop analogy, door locking and turning off the car really have nothing in common. Consider that the doors also lock when the car is actually being used/driven.

For what its worth, I ALWAYS turn the car off with the "start button". I like to see it shut down before I leave (and it also automatically moves the seat backwards a little to make egress - and subsequently ingress - easier). I also very rarely lock my car as it sits in a pretty secure garage. So my car is always "shutdown" and "unlocked" when it is on the charger at home...

 

[NC_Taycan]

For what its worth, I ALWAYS turn the car off with the "start button". I like to see it shut down before I leave (and it also automatically moves the seat backwards a little to make egress - and subsequently ingress - easier). I also very rarely lock my car as it sits in a pretty secure garage. So my car is always "shutdown" and "unlocked" when it is on the charger at home...

Same here (car in garage, unlocked, turned off via power button). 12V battery dead one time since April, nothing else 12V related. At the time of death, Taycan was connected to PMCC, and I'm pretty sure I changed a charging timer via the Connect app while it was connected.

 

[evanevery]

Same here (car in garage, unlocked, turned off via power button). 12V battery dead one time since April, nothing else 12V related. At the time of death, Taycan was connected to PMCC, and I'm pretty sure I changed a charging timer via the Connect app while it was connected.

The theory holds.

I'm betting you can discount everything but "Porsche Connect"...

However, I've got no skin in the game (hopefully) as I don't use Porsche Connect or Timers to alter my charging parameters...

{sounds of searching desperately for some wood to knock on}

 

[Las Vegas Taycan]

I am the latest victim. Car was plugged into the charger but not driven for about 2 weeks. When I went to drive it today. Nothing. had to get Porsche out to tow it to the dealer.....UGH...

 

[ejcintr]

I am the latest victim. Car was plugged into the charger but not driven for about 2 weeks. When I went to drive it today. Nothing. had to get Porsche out to tow it to the dealer.....UGH...

Is it always recommended to get it to the dealer when the 12v issue happens- if I can get the car backup and running by accessing the frunk and boosting the 12v why bring it in.. unless the dealer is going to update the cars sw... they don't do anything. Is it for warranty purposes?

 

[daveo4EV]

it’s to make it cost porsche $$$ to deal with the issue - otherwise it will go unnoticed and unresolved because porsche will lack incentive to “fix” it...

also it might not be “the 12V“ issue - only service tech’s can actually pull the vehicle logs to check it out.

 

[ejcintr]

it’s to make it cost porsche $$$ to deal with the issue - otherwise it will go unnoticed and unresolved because porsche will lack incentive to “fix” it...

also it might not be “the 12V“ issue - only service tech’s can actually pull the vehicle logs to check it out.

Got it.. but to be frank... if it does happen to me its gonna depend upon the wait for porsche to send someone out to tow the car to the porsche dealer (and if they send someone who knows what to do).. vs. me doing it in 20-30 minutes to bootstrap the car... well thats gonna be a game day call for me.

 

[Las Vegas Taycan]

Car returned and said all was fine. Went to drive it and DOA....so again Porsche Assistance and a TOW...How many times before you call it a lemon?

 

[daveo4EV]

In california 3 times for the same issue in the first 18 months of vehicle warranty.

 

[W1NGE]

I'm calling BS on this... (Like so many other things dealerships seem to be clueless about)

If this truly is a car which I need to manually manage the charging process - then they can take it back. (Even Porsche software designers wouldn't be so stupid to make this mistake).

EV ownership is so much more convenient as ICE ownership as all you SHOULD need to do is plug your car back in when you get home. I've been doing this with 4 different EV's over the last 7 years or so. If I had to unplug my Taycan instead of leaving it plugged in then this truly would be a departure from what is acceptable.

My car has been sitting on the charger everytime/anytime it is parked in my garage (since August). Even if I just roll it out to wash it - it still gets plugged back in when I pull it back inside. Its always sitting there (at 85% charge) waiting for me. I don't use timers, custom profiles, or Porsche Connect. I just plug it in. Done.

People (and SC's) need to recognize that just because a car is "plugged in" doesn't mean its also "charging". The onboard charger is responsible for determining if/when the car should be charging (and when it should not). Is that lamp on your living room table always turned on? Its always plugged in, right? "Plugged In" does not mean "Charging"!

Its much more likely that something is waking up the PCM (Porsche Connect or Timer) and the PCM is not shutting down again and draining the 12V battery. Its not that the car is plugged in, its that something is "waking it up" while its plugged in...

Perhaps they are suggesting you "don't keep your car plugged in" so there is no REASON to wake it up? IOW: There is little point in setting a timer or using PC to adjust charging parameters if the car isn't plugged in... If this is truly what their angle is, then I would submit they would simply be better off asking folks not to use Timers or Porsche Connect until they resolve their problem.

How do you charge and keep to 85% without setting a profile or timer?

 

[Gogs]

You have to set a general profile to 85%.

 

[W1NGE]

I am the latest victim. Car was plugged into the charger but not driven for about 2 weeks. When I went to drive it today. Nothing. had to get Porsche out to tow it to the dealer.....UGH...

Precisely that's why i queried it - impossible otherwise.

The chap earlier in the thread said he doesn't use any timer, profile or Connect App.

 

[Steve]

ooops.......

Sorry i see the same problem yesterday did you find any solution my car made it 2 times ?

Yes. This is the same issue that I have. Mine only happened after the software update. It does reset itself after 15 mins. Dealer did the DME patch software update. But this may not the be right fix. My car experienced the same error again after the fix. It is very random and so far, infrequent for me. Going back to dealer next week.

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