Software update decreasing range of 4S and making the car think it is RWD with smaller battery

[DMTaycan]

I am starting this thread to entice Porsche to take notice of this issue. I understand such issues can occur.

My 2020 Taycan 4S had been flawless over 2 years and 28000 miles. After a long wait, the car had its major software update and it was not great.
1. The car instead of reporting the usual 260 miles of range [based on my usual driving] dropped to about 220 miles.
2. The car reported the need for a further over the air update as soon as I got it back home. This was more disastrous, it resulted in the car reporting incorrectly that the car was not connected to a charger, lost all profiles and times, stopped reported percentage charge, but kept updating the miles forecast. The Porsche app showed a charging error and was stuck at 40% charge, but updating the miles forecast. Porsche dealer suggested contacting Porsche recovery as there would have been a long wait for a further slot at service. Porsche recovery sent AA team and after disconnecting and reconnecting the 12 V battery this latest error [charger not connected] disappeared, but it did not change the reduced range
3. I have also noticed that my left instrument cluster stopped showing the all wheel information as if it was RWD. I initially assumed that I just needed to reconfigure some options, but after delving into all options and looking into this forum, I can only conclude that the software update is responsible for the car believing it is RWD with reduced range and no need to show all well drive info.
I have reported this via the Porsche up as a bug to feedback to the Porsche software engineers.
4. After contacting my Porsche dealer, I was told that my car was the second Taycan 4S to have this issue of decreased range and it was resolved by redoing the software update again. I am now awaiting to take it back to the dealer.

So, I recommend that
1. Do not allow the over the air software update following the dealer major software update, as it will mess thing up. The over the air update claimed that it improves compatability with more public chargers and improves accuracy of reporting range. Don't allow this update yet
2. If your car reports decreased range [rather than increased range as was supposed to be the case with this update], don't assume it is necessarily the colder weather or that the car will recalibrate again. Better report this to Porsche dealer and revisit the possibility of re-doing the major software update.

Thanks

 

[Windpower]

The car instead of reporting the usual 260 miles of range [based on my usual driving] dropped to about 220 miles.

We call the number which the car shows as coming from a 'guess-o-meter'. This number is a guess based on past history. You need to ignore this number until you have some number of miles on your car post update. The software update wiped out your driving history so you are starting from scratch and the calculation is bad.

The most accurate indicators in the car are 'state of charge' and 'miles per kwh'. State of charge is displayed as a percentage of the available capacity of the battery. Miles per kwh shows how much power your driving style requires. Both of these can be used to figure out how many miles you can go on a charge.

But the 'guess-o-meter' is just that: a guess.

After a couple of weeks of driving, if you have actual loss in range, there might be something to consider looking into. But right after the update, you might want to ignore it.

As for the car thinking that it's a RWD, that is something you might want to go back to the shop to have fixed.

 

[TAYC4S]

I might be that other owner. I had the issue last week and reported to Porsche head office. This is what Porsche Germany advised and has resolved the issue. It is not related to the major software update.

The OTA update has possibly corrupted something as the first thing recommended by Germany was to do another update - I think/feel this one is internal only - ie not something widely being done. That changed nothing - so in my mind was not required. In fact if anything it made things worse because between Thursday (when the update was done) and Sunday, the range dropped every day whilst the % showing remained at 0%.

On Monday this week, Porsche Germany then advised a power charger controller "hard reset" - not sure what that entails but, it fixed the issue and the car is back to me all well and good.

Its now sitting at 85% charge and 229 miles. BTW after the software update the car might take a few miles to re-calibrate range as well so I would not worry too much on range estimates until you have driven it for a few weeks post the update.

I think the AA disconnecting/reconnecting the 12V does not achieve anything - if anything it might have made the issues worse, fixing some whilst creating others, but that is just me speculating.

The OTA update clearly tripped something and required a hardware reset on the Power controller unit.

Porsche HQ in Reading is fully aware of the issue - as I had reached out to them over the weekend.

 

[DMTaycan]

We call the number which the car shows as coming from a 'guess-o-meter'. This number is a guess based on past history. You need to ignore this number until you have some number of miles on your car post update. The software update wiped out your driving history so you are starting from scratch and the calculation is bad.

The most accurate indicators in the car are 'state of charge' and 'miles per kwh'. State of charge is displayed as a percentage of the available capacity of the battery. Miles per kwh shows how much power your driving style requires. Both of these can be used to figure out how many miles you can go on a charge.

But the 'guess-o-meter' is just that: a guess.

After a couple of weeks of driving, if you have actual loss in range, there might be something to consider looking into. But right after the update, you might want to ignore it.

As for the car thinking that it's a RWD, that is something you might want to go back to the shop to have fixed.

I fully understand that. I have driven this car for 28 thousand miles. The Porsche dealer confirmed that this same issue with decreased range occurred to another Taycan following the software update which was later corrected by re-doing the software update. So it is not simply the car is guessing, it is the software reporting inaccurate info.

I also found out that my miles per kWh remains as before. Furthermore, you are wrong in saying that the update has wiped out the driving history. It did not and I can still view my driving history and miles per kWh since I purchased the car as well as the software sessions in my Porsche app on my desktop but not on the phone.

It is not only the need to correct these glitches, but over the last 2 years, I trusted totally the Porsche's prediction of range on my long trip, something essential for planning long trips, so the need for correcting this is not merely frustration, it is also essential aspect of driving EVs

Thanks for your reply

 

[DMTaycan]

I might be that other owner. I had the issue last week and reported to Porsche head office. This is what Porsche Germany advised and has resolved the issue. It is not related to the major software update.

The OTA update has possibly corrupted something as the first thing recommended by Germany was to do another update - I think/feel this one is internal only - ie not something widely being done. That changed nothing - so in my mind was not required. in fact if anything it made things worse because between Thursday (when the update was done) and Sunday, the range dropped every day whilst the % showing remained at 0%.

On Monday this week, Porsche Germany then advised a power charger controller "hard reset" - not sure what that entails but it fixed the issue and the car is back to me all well and good.

Its now sitting at 85% charge and 229 miles. BTW after the software update the car might take a few miles to re-calibrate range as well.

I think the AA disconnecting/reconnecting the 12V does not achieve anything - if anything it might have made the issues worse, fixing some whilst creating others but that is just me speculating.

The OTA update clearly triped something and required a hardware reset on the Power controller unit.

Porsche HQ in Reading is fully aware of the issue - as I had reached out to them over the weekend.

Thanks very much for the info

 

[DMTaycan]

Thanks very much for the info

By the way, the other car was in East London so there maybe more affected

 

[W1NGE]

PIRM seems to have reappeared and can be configured again.

 

[DerekS]

I am pretty sure the AWD display got moved from the instrument cluster to the main PCM display.

I'm interested to see if you can find it in there somewhere (maybe under Vehicle?) and if it shows front motor engagement as you drive.

EDIT: Forgot the pull quote to give this context

 

[W1NGE]

Car - Trip - animated display:

 

[Windpower]

The Porsche dealer confirmed that this same issue with decreased range occurred to another Taycan following the software update which was later corrected by re-doing the software update.

So it is not simply the car is guessing, it is the software reporting inaccurate info.

I also found out that my miles per kWh remains as before.

The point is that you have not lost range, which your thread title indicates:

"Software update decreasing range"

You have the same range, but the range indicator on the car is wrong. This might be a software bug or it might be a setting which was not reset or reset with bad values.

But certainly your car has not lost range.

 

[B61]

Why started a new thread?
We already discussed all of your issues.

 

[ciaranob]

For reference it took three weeks with three separate at home charging sessions to 85% each time for my car to 'recover' to my pre-uPdate max. predicted ranges.

I have not seen any increase at all in overall range post-uPdate but also not terribly surprised by this. And before anyone jumps on it, variables such as temp, road trip length, driving style, elevations, and all else near identical pre and post uPdate.

 

[DMTaycan]

The point is that you have not lost range, which your thread title indicates:

"Software update decreasing range"

You have the same range, but the range indicator on the car is wrong. This might be a software bug or it might be a setting which was not reset or reset with bad values.

But certainly your car has not lost range.

Thanks, I hope you are right
However, my understanding is software is able to allocate buffers at the top and bottom ends and likely also influence the car efficiency, Therefore, while I hope you are right, this "indicated" range will remain a cause of concern until fixed

 

[DMTaycan]

For reference it took three weeks with three separate at home charging sessions to 85% each time for my car to 'recover' to my pre-uPdate max. predicted ranges.

I have not seen any increase at all in overall range post-uPdate but also not terribly surprised by this. And before anyone jumps on it, variables such as temp, road trip length, driving style, elevations, and all else near identical pre and post uPdate.

Thanks, I am sure you could be right, but this is really very different from previous updates experience and does not explain other issues such as the issue with the instrument cluster

I will update this if and when the dealer do the software update again

 

[DMTaycan]

I am pretty sure the AWD display got moved from the instrument cluster to the main PCM display.

I'm interested to see if you can find it in there somewhere (maybe under Vehicle?) and if it shows front motor engagement as you drive.

EDIT: Forgot the pull quote to give this context

Thanks, unfortunately it has not. I checked again following your reply

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