OTA Update - WTD4 - Battery monitoring

[P-fan]

Same same...

"High-voltage battery control unit-WTD4" was installed 2 days ago with no hiccups. I can't find anything else online that specifically says what this addresses. My car is MY 2021 4s.

Curious if they took the opportunity to fine-tune anything about the PCM...

I doubt anything was fine-tuned in the PCM during this update. I took a picture of the version numbers of all software components before and after the WTD4 update, and they were all unchanged.

Sponsored

 

[P-fan]

Mine failed the first time, waited 45 minutes or so tried later and it worked. Everything was very sluggish on PCM when I got back to car after upgrade and it wouldn’t play music from radio, usb or CarPlay, worked on next restart though.

For me, the update worked right away. However, after the update had completed, the PCM initially came back, then "crashed" after 30 seconds. When it came back up, I went into the software versions menu, and all versions/dates were blank (well, it showed dashes instead of version numbers). After I restarted the car, all was fine.

Update: I see now this is exactly what @Tango22 and @Leccy61 mentioned as well.

 

[fsolis]

I received the update yesterday. Like some of you, my CarPlay wasn’t working and there was no audio. After manually restarting the PCM, everything is working fine now.

 

[Mizzle51]

There is a TIB from Porsche on another thread WSH4 from America which sounds identical, I wonder if the number change (WSH4 to WTD4) indicates a Region change for the same issue.

I could be wrong but there is an interesting paragraph that says:
The vehicles affected by this campaign were built or repaired using a high-voltage battery that was manufactured after the date of use ("clean date") of the optimized high-voltage batteries. Therefore, these vehicles are not covered by the recall campaigns ARB6 or ARB7.

Interesting? See attached.

Oddly enough my car service history indicates it got WSH4 last year and now I was prompted for WTD4 today. Perhaps a new revision of that same fix?

 

[gnr3312]

Finally got mine to install. Turns out I had to power off AC from the main AC screen, not just from the track screen.

 

[whitex]

Tried applying mine 3 times - failed every time. The second time I sat there to babysit it:

Sat there for 5-10 minutes, it failed:

So I went back to read instructions:

Ok, tried searching in PCM for "stationary air conditioning" to disable, zero hits. Went beyond that, tried to find any setting under HVAC screen, nope, under vehicle settings, nope, the closest I could find was "Precool/heat", it was already Off.

Since I wasn't planning to remove unlock, the bottom option doesn't seem relevant.

Anyways, tried again, this time the update was still showing under "Updates" not will not appear when I turn the car Off.

Porsche is so out of their depth on software it's not funny. I feel like I put significantly more effort into this than an average customer would. If a customer who actually paid attention to an info popup in the middle of driving which disappeared shortly thereafter, who actually wants to apply the update, is unable to do so, then the utility of OTA updates for Porsche is near zero, i.e. effectively useless. They are going to have to charge half a million dollars per car just to account for the car's lifetime of OTA updates Porsche will have to pay dealers to apply.

 

[Sace]

Porsche is so out of their depth on software it's not funny. I feel like I put significantly more effort into this than an average customer would. If a customer who actually paid attention to an info popup in the middle of driving which disappeared shortly thereafter, who actually wants to apply the update, is unable to do so, then the utility of OTA updates for Porsche is near zero, i.e. effectively useless. They are going to have to charge half a million dollars per car just to account for the car's lifetime of OTA updates Porsche will have to pay dealers to apply.

Since the can manage to brick the PCM when trying to do an update it is no surprise that OTA is this bad

Btw. I always removed the charging cable entirely - Updates would not install as long as it was in no matter if it was charging or not.

Have not had this update yet (or maybe they installed it while the car had it's PCM replaced, who knows).

 

[Taycan4S_UK]

No. 2020 have a different chemistry. In 2021 they changed the chemistry. Then in Q4 2024, they updated their manufacturing procedures to address the manufacturing defects for celss produced from 2019-2024 Q3

Then j1.2 has entierly different cells, new chemistry, new manufacturing, and the battery enclosure is slightly updated also. The cells are still from LG Chem, same as previous year taycans.

My car, a 2020 turbo, has most modules from 2020, 2 modules from a 2023 car, and 1 module from after Q4 2024. So I have 3 types of cells in my battery - 2 chemistries.

Wonder if the BMS can actually differentiate them when monitoring them.

Mine is a early MY21 (has heads up display and remote lock/unlock) - does that it has updated chemistry over MY20 model?

 

[chun]

Mine is a early MY21 (has heads up display and remote lock/unlock) - does that it has updated chemistry over MY20 model?

Yes, it’s different than 2020

 

[Taycan4S_UK]

Is there any official doc ? - everything I read say it's all the same until MY25 when the new battery chem was introduced.

 

[whitex]

Btw. I always removed the charging cable entirely - Updates would not install as long as it was in no matter if it was charging or not.

That did the trick. Apparently "stop the battery charging process" for the Germans means "unplug the source of power", not just stop charging via a command or wait until it's done. I guess "turn off your headlights" must mean "unplug your headlights" and "stop your car " must mean "disconnect the traction HV battery".

Of course the first drive after successful OTA was lacking all connectivity, CarPlay would not connect, Spotify music streaming would not work. 2 finger engineering reset fixed it, but come on Porsche, doesn't anyone with any power at the company use their own products and realize how ridiculous the user experience is? Or do they all drive Teslas and in their heads generalize "Tesla has OTA, Porsche has OTA - they both have the same feature, CHECK!"?

PS> 2 finger reset is gone from J1.2 and J1.3. I guess Porsche is laser focusing on those Porsches intended as investments and garage decorations - nobody cares if OTA works on those (as long as Porsche is legally covered via the "we offered OTA update, not our fault customer chose not to install it by following instructions"), nor whether car is fully functional after the OTA update - it stores just as well, shines just as well. *sigh*

 

[Tooney]

Why would any owner try to do an OTA update while a charging cable is plugged into the car?

 

[Sly_North]

I'm not sure WTD4 is the same as WSH4, but can't be certain. It's interesting though that this note acknowledges that the battery is different accross cars within the same J1.1 generation. I always had the impression that all J1.1 cars have the same spec battery.

See CT14's comment there. The global design is similar (though there was a simplification of the battery cooling piping at some point), but there's been several generations of battery modules :
- C-> 2019/2020 "terrible they always fail"
- G-> 2020/2021
- H-> 2021/2022
- J-> 2022/2023
- K-> 2024+
etc.

 

[Tooney]

Is there any official doc ? - everything I read say it's all the same until MY25 when the new battery chem was introduced.

A couple of TSBs related to different HV batteries in model years:
https://static.nhtsa.gov/odi/tsbs/2022/MC-10219388-0001.pdf
https://static.nhtsa.gov/odi/tsbs/2025/MC-11024023-0001.pdf

 

[Tango22]

Pleasantly surprised to find since I carried out the update I've gained about 10 miles of range on the dash 'guessometer', although I expect that'll drop gradually over the next few weeks as the car recalibrates/readjusts to my driving style.

Sponsored