Losing power issue

[AlexPx]

Hi everyone.

So finally I also got this message. Gladly I was fast enough to leave the autobahn but came to a stop at the side lane of the exit. Turned it off and on again. Everything was working again. When the message occurred, I could not accelerate any longer, just braking without recouperation and steering.

Possible reason: I switched the internet radio stations and then the the top line of the favourites disappeared. The pcm, upper Display in the middle, freezed and stopped working. The lower display eg navi or music button „clicked“ but the pcm didn’t react. The two finger trick didn’t work either. The navigation with range manger was active before that happens.

Driving still worked without a problem.

But then I changed from sport plus to sport mode with the knob on the steering wheel. The moment I turned it the message occurred and the car stopped.

My opinion - non expert, not even too interested in computer technology- the pcm freezed like a windows Computer. With changing the mode, the „driving computer“ tried to communicate with the pcm, maybe for telling the navigation that an other drive mode was acitivated. The pcm didn’t answer, so the car went totally on error.

My suggestion: if the pcm freezes or stops working during driving, don’t change the mode. Just drive to the next parking and turn the car off an on.

I informed the dealer. They checked the car and forwarded the problem to porsche. But there is no solution yet.

Car: 4s 2021 after the big update.

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[AlexPx]

Just want to add: it’s not to nice to have to stop and restart, but the car is still a hell of a ride and I still love drive it every day.

 

[IBZman]

Hi Everyone,

This is my first post here!

AlexPX, thank you so much for this. As someone who has a Taycan on order, I have to admit, this issue has spooked me. I have a tech background, so I understand that bugs can be annoying, frustrating, or problematic. However, this is potentially lethal and is worrying.

Your post though - and more importantly your report back to Porsche - is precisely what is needed.

Wearing my techie hat, issues like this are a nightmare to track down. They are intermittent and seemingly random. But there will almost certainly be an action, an event, or a pattern of events which is triggering the car simply shutting itself down. This is why your post-mortem of events leading up to the car failing is so important.

I think would be great if everyone who has experienced this issue replies to this thread stating exactly what they were doing and what the car was doing immediately prior to their car cutting out, just like AlexPX has done.

This information could be vital in helping Porsche find the issue.

The key here is repeatability. Porsche need to have as much information as possible to be able to repeatedly recreate the issue - e.g. speed, distance travelled, charge level, what was being changed on the PCM etc...

 

[feye]

Hi Everyone,

This is my first post here!

AlexPX, thank you so much for this. As someone who has a Taycan on order, I have to admit, this issue has spooked me. I have a tech background, so I understand that bugs can be annoying, frustrating, or problematic. However, this is potentially lethal and is worrying.

Losing power in that situation for a half way skilled driver is not an issue, just hit the hazard warning light and get to the right side. The car coasts, breaking and steering works.

 

[Raedwald]

When it happened to me I wasn't doing anything with the PCM and it was behaving normally. I was just driving and then the warning came up and then I could not move the car. This happened to me in October last year. I am staggered that Porsche have not fixed this issue yet and continue to sell cars knowing this issue exists.

 

[faroutinNM]

This information could be vital in helping Porsche find the issue.

The key here is repeatability. Porsche need to have as much information as possible to be able to repeatedly recreate the issue - e.g. speed, distance travelled, charge level, what was being changed on the PCM etc...

As a retired control systems engineering veteran of similar systems (except these were airborne), I applaud this insight. Users operating these systems of ever-higher complexity, automation, and reliance on software capabilities will find issues under conditions that may not have been tested, and typically cannot be resolved with certainty until they can be duplicated in testing. The most difficult to troubleshoot and resolve are those that occur "intermittently". Moreover, a few issues may emerge only after countless thousands of hours of operation in real-world conditions. Users will be understandably frustrated by this reality, but I've worked with many issues like this that aircrews (mostly military in my case) discovered and dutifully logged, while taking calm actions to mitigate any resulting hazard (and patiently waiting for and validating the implemented resolution). Still, development and testing engineers of the system (like me) have already resolved thousands of issues (mostly software-related) before and during ground and flight testing, all before any new system version has been certified for operation, but this doesn't guarantee that lurking issues might not emerge, some soon after certification, some of them years later.

As an aside, loss of control in the air can be fatal, as it can on the road in the midst of traffic or at high speeds. Loss of power, though, can be managed if the system proves to be still controllable with that failure. The Taycan, as has any production car, has been designed, and tested countless times, for controllability under many diverse loss-of power conditions. With that in mind, drivers should be prepared to take action in response to the unexpected. No surprise to any of us there.

Finally, whether or not use of the system is restricted is a matter regulated by the agencies designated as responsible in a given jurisdiction, and the applicable legalities in it. There is always an inherent risk (statistically a huge one) in operating any car on the roadway, yet drivers globally take that risk routinely in incalculable hours of driving. Mass transit is overwhelmingly safer. It's instructive to see a sober reminder of that. And, among the countless hours of operation there are countless opportunities for incorrect use that also need to be analyzed for possible remedy. It's not to be used as an excuse for flaws in the Porsche Taycan or any production car model, though. And the good news is that many new and recently available assistance features considerably reduce the mental load on the driver, providing vital situational information, warnings, guidance, and alerts during driving. As a result, we could see improved traffic accident statistics in the future. We'll see.

 

[chrisk]

I disagree with both IBZMan and faroutinNM.
Relying on owners to remember what buttons they pushed while driving is an archaic way to debug problems. The car should log its state, all variables and the user inputs when errors occur. It should also self-correct/recover when possible.
Unfortunatelly Taycan doesn't do either in most cases. I myself have had several warnings with "service required" message and the car recorded nothing useful for the dealer to investigate.

p.s. I am also in the field. If I tell my company to ask users to provide info for debugging issues they would laugh at me and maybe I would get fired. But I have worked in other companies that did it so I understand. They are just at completely different levels of software capabilities, one being error logging.

 

[NC_Taycan]

There is another thread going on about an issue (post-update) involving communications between the DME and the rear motor control electronics (and potentially involving an impossible rotor position sensor output). There is a software update (separate from the big update). Beyond this I have no idea if this is something that might exist in all cars (so don't yet rush to your dealer and ask for an update that might not exist), and I imagine there has to be a specific sequence of events to cause the error. If it's just a communications issue (software), no hardware is actually broken which is why shutting off the car makes it go away. It's still dangerous, and any occurrence needs to be reported - we need Porsche to act on this for our safety.

 

[faroutinNM]

I disagree with both IBZMan and faroutinNM.
Relying on owners to remember what buttons they pushed while driving is an archaic way to debug problems. The car should log its state, all variables and the user inputs when errors occur. It should also self-correct/recover when possible.
Unfortunatelly Taycan doesn't do either in most cases. I myself have had several warnings with "service required" message and the car recorded nothing useful for the dealer to investigate.

p.s. I am also in the field. If I tell my company to ask users to provide info for debugging issues they would laugh at me and maybe I would get fired. But I have worked in other companies that did it so I understand. They are just at completely different levels of software capabilities, one being error logging.

I think we're in agreement.

I'm only saying that the first indication of an aircraft problem is sometimes a crew observation. The next step would be to examine the system's internal and transmitted data records to further troubleshoot. And haven't we all seen error messages that are less specific than we'd like? Often, it's going to take some human investigation to nail it down and correct it. Yes, we design some self-diagnosis and self-correction, but it's not going to apply to every unforeseen issue.

Anyway, I trust we're on the same page here.

 

[AlexPx]

Losing power in that situation for a half way skilled driver is not an issue, just hit the hazard warning light and get to the right side. The car coasts, breaking and steering works.

As I was near to the exit and there was an emergency lane it was no problem at all. But the same happening while overtaking, on a winding road through the woods or in a construction area with no emergency lane might be annoying. At least cause of some honks honking

 

[AlexPx]

As a retired control systems engineering veteran of similar systems (except airborne), I applaud this insight. Users operating these systems of ever-higher complexity, automation, and reliance on software capabilities will find issues under conditions that may not have been tested, and typically cannot be resolved with certainty until they can be duplicated in testing. The most difficult to troubleshoot and resolve are those that occur "intermittently". Moreover, a few issues may emerge only after countless thousands of hours of operation in real-world conditions. Users will be understandably frustrated by this reality, but I've worked with many issues like this that aircrews (mostly military in my case) discovered and dutifully logged, while taking calm actions to mitigate any resulting hazard (and patiently waiting for and validating the implemented resolution). Still, development and testing engineers of the system (like me) have already resolved thousands of issues (mostly software-related) before and during ground and flight testing, all before any new system version has been certified for operation, but this doesn't guarantee that lurking issues may emerge, some soon after certification, some of them years later.

As an aside, loss of control in the air can be fatal, as would be true on the road in the midst of traffic or at high speeds. Loss of power, though, can be managed if the system proves to be still controllable with that failure. The Taycan, as has any production car, has been designed, and tested countless times, for controllability under many diverse loss-of power conditions. With that in mind, drivers should be prepared to take action in response to the unexpected. No surprise to any of us there.

Finally, whether or not use of the system is restricted is a matter regulated by the agencies designated as responsible in a given jurisdiction, and the applicable legalities in it. There is always an inherent risk (statistically a huge one) in operating any car on the roadway, yet drivers globally take that risk in incalculable hours of driving. Mass transit is overwhelmingly safer. It's instructive to see a sober reminder of that. And, among the countless hours of operation there are countless opportunities for incorrect use that also need to be analyzed for possible remedy. It's not to be used as an excuse for flaws in the Porsche Taycan or any production car model, though. And the good news is that many new and recently available assistance features considerably reduce the mental load on the driver, providing vital information and alerts during driving. As a result, we could see much safer driving conditions in the future. We'll see.

I do agree. Only thing: I didn’t use anything incorrect. So the correct but obviously untested use lead to the problem.

 

[AlexPx]

I disagree with both IBZMan and faroutinNM.
Relying on owners to remember what buttons they pushed while driving is an archaic way to debug problems. The car should log its state, all variables and the user inputs when errors occur. It should also self-correct/recover when possible.
Unfortunatelly Taycan doesn't do either in most cases. I myself have had several warnings with "service required" message and the car recorded nothing useful for the dealer to investigate.

p.s. I am also in the field. If I tell my company to ask users to provide info for debugging issues they would laugh at me and maybe I would get fired. But I have worked in other companies that did it so I understand. They are just at completely different levels of software capabilities, one being error logging.

Well in my case the car did a log file but it was corrupted by me doing the 2 finger reset after restarting and parking just for sure. But Porsche told that if I ever have the issue again, I should just stop the car and get it towed by assistance to the shop. They’ll than analyse it.

 

[atebit]

Logs like that should be stored in an area that’s only clearable by a diagnostic tool, not in “user space”.

 

[faroutinNM]

I do agree. Only thing: I didn’t use anything incorrect. So the correct but obviously untested use lead to the problem.

I apologize if I was unclear. I didn't intend to imply that you did anything incorrect. I just meant that is a possibility that needs to be included in any analysis in general.

 

[AlexPx]

I apologize if I was unclear. I didn't intend to imply that you did anything incorrect. I just meant that is a possibility that needs to be included in any analysis in general.

No need for that. Everythings fine. Just wanted to state, that the error occurs with correct usage.

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