[CONFIRMED&DANGEROUS] 9J1.2 LETS YOU DRIVE WITH POOR ISOLATION AS WELL

[ct14garage]

es it does.
If there's no or minor change in isolation value (due to low conductivity) there will be no detection.
I know what you mean by ignoring the readings but there's a difference this time.

Low conductivity = no change in isolation value (within the envelope that is).
Higher conductivity = significant change in isolation value (but ignored by the BMS to a certain extent).

Any water inside the battery (be it coolant or flood water) almost instantly drops the isolation from 550 mega ohms (infinity) to 0.X mega ohms (very poor).

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[Dee]

not sure what there is to discuss here.

That that little amount of coolant can cause a short circuit but if that amount was rain/fresh water it wouldn't.
Big difference imho.

 

[ct14garage]

That that little amount of coolant can cause a short circuit but if that amount was rain/fresh water it wouldn't.
Big difference imho.

It may not cause the short circuit as fast as coolant did (I have certainly seen several water logged batteries with rain / fresh water and none shorted. The first battery water logged with coolant I ever see has in fact shorted).

But the isolation was poor in all those batteries.... even the fresh water ones.... 0.X mega ohm on each of them. Under no circumstances should the BMS allow the high voltage system to activate with such low isolation.

For reference BYD EVs open the battery contactor when isolation reaches 30 mega ohm. Taycan still drives and charges with 0.X mega ohm in battery.

 

[Jasper4S]

Interesting case, and it is good that experiences like this are being shared. I certainly do not doubt the knowledge or skill of @ct14garage who worked on it. Again nice find.

It is worth keeping in mind though that this happened in Thailand, where there are no official Porsche dealers. That means software updates, service campaigns and potential recalls may be delayed or not implemented at all. Combined with the tropical climate, with high humidity, heat and heavy rainfall, conditions like these can make leaks or isolation issues develop much faster than they would here (talking about EU and nothern America)

One incident, however serious, does not mean that all 150,000 Taycans are at risk. Lets not get in another panic mode like last time when we all thought 60% of the batteries were bad and need replacements just 1 hour after 8 years of warranty.

 

[THAICAN]

Interesting case, and it is good that experiences like this are being shared. I certainly do not doubt the knowledge or skill of @ct14garage who worked on it. Again nice find.

It is worth keeping in mind though that this happened in Thailand, where there are no official Porsche dealers. That means software updates, service campaigns and potential recalls may be delayed or not implemented at all. Combined with the tropical climate, with high humidity, heat and heavy rainfall, conditions like these can make leaks or isolation issues develop much faster than they would here (talking about EU and nothern America)

One incident, however serious, does not mean that all 150,000 Taycans are at risk. Lets not get in another panic mode like last time when we all thought 60% of the batteries were bad and need replacements just 1 hour after 8 years of warranty.

AAS Auto Service Co. Ltd. is the sole authorized distributor and importer of Porsche in Thailand since 1986.

There are multiple locations, including Porsche Centre Bangkok, Porsche Centre Bangna, and Porsche Centre Pattaya, along with city showrooms in locations like Siam Paragon and Iconsiam.

 

[Jasper4S]

Good point, thanks for clarifying that AAS is the official Porsche distributor in Thailand. I was under the impression this was handled mainly by independent shops. Like CT14 garage.

That said, the local climate and conditions in Thailand are still very different from Europe or North America, and issues like coolant leaks or insulation faults can develop faster in that kind of environment. It would also be interesting to know whether this particular car had received all the latest software and service updates. One case like this does not necessarily indicate a widespread issue.

Just curious, @ct14garage — you run an independent garage, right? Are you able to perform all official recalls? Do you apply them immediately or only when customers bring their cars in for other work?
I am not trying to downplay this thread at all; I just want to make sure the story here stays clear and accurate before some random journalist or YouTuber spins it into an another half-true headline.

 

[ct14garage]

Just curious, @ct14garage — you run an independent garage, right? Are you able to perform all official recalls? Do you apply them immediately or only when customers bring their cars in for other work?
I am not trying to downplay this thread at all; I just want to make sure the story here stays clear and accurate before some random journalist or YouTuber spins it into an another half-true headline.

I apply the recalls when customers bring their car to me.

But the matter of fact is that this is a 9J1.2 (2025 car), not the old model. And this is also an official car bought from the local Porsche dealer which had received all services at the local dealer so far. When battery popped they came to me.

I think it's quite serious because this problem was in the pre facelift Taycans and very clearly still is in the new model!!! It should have been fixed long ago

when isolation drops below 30 mega ohm battery contactor should open as it does in the Chinese EV.

Every single Taycan out there in the world will drive with 0.X mega ohm isolation in the battery. This is very dangerous.

How many of those Taycans will reach these conditions of low isolations is another matter. Most of them obviously will never be in such a situation. But the risk is still there the moment something goes wrong. Be it water inside the battery or degraded cells....

 

[Dee]

Good point, thanks for clarifying that AAS is the official Porsche distributor in Thailand. I was under the impression this was handled mainly by independent shops. Like CT14 garage.

Me too.
I can't recall who said that though but he's on this forum as well.

 

[Jasper4S]

I apply the recalls when customers bring their car to me.

But the matter of fact is that this is a 9J1.2 (2025 car), not the old model. And this is also an official car bought from the local Porsche dealer which had received all services at the local dealer so far. When battery popped they came to me.

I think it's quite serious because this problem was in the pre facelift Taycans and very clearly still is in the new model!!! It should have been fixed long ago

when isolation drops below 30 mega ohm battery contactor should open as it does in the Chinese EV.

Every single Taycan out there in the world will drive with 0.X mega ohm isolation in the battery. This is very dangerous.

How many of those Taycans will reach these conditions of low isolations is another matter. Most of them obviously will never be in such a situation. But the risk is still there the moment something goes wrong. Be it water inside the battery or degraded cells....

Thanks for adding that nuance.

 

[jk981]

How the hell have they not addressed this issue in J1.2? Is it even fixable at this point?

 

[rim23]

If there is official dealer, why would someone go to an individual garage rather than the official dealer?? The case must be handled under warranty free of charge…

 

[ct14garage]

How the hell have they not addressed this issue in J1.2? Is it even fixable at this point?

A mere software update to the BMS would solve it....

 

[Jasper4S]

My thoughts too @rim23. Is it a distance thing @ct14garage?

 

[ct14garage]

My thoughts too @rim23. Is it a distance thing @ct14garage?

Because a lot of Taycan in Thailand have been bought from Porsche Centre East London in the UK and imported into Thailand by third party dealers which are not Porsche. This is what we call grey imports, local Porsche dealer won't service such cars even if self paid.

However in the case of this 9J1.2 that suffered a short circuit, it's an official Porsche imported car, but the queue for service was months long so customer prefers to pay to repair with us given that as of today he is already back on the road. Had he waited for Porsche to even look at it the first slot was end of January 2026

 

[Dee]

How the hell have they not addressed this issue in J1.2? Is it even fixable at this point?

I don't think this is a common thing.
These battery cases are being pressure-tested and only a few don't qualify through QC and the only one that somehow managed to get through while it shouldn't ends up here in this topic.

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