Porsche unable to engineer a reliable heater?

[F1Ruaraidh]

They presumably design the car, therefore should be vetting the design and reliability of the parts they choose to put into their designs. If the wheels started falling off and continued to do so for years, would you say "Porsches are solidly designed cars, ignore the wheels falling off, that's the wheel supplier's fault".

Sadly that depends on how good your validation programme is and the design of that depends on your experience with the underlying technology.

Hence Taycan full of EV issues and Model S full of basic car issues - wipers, lights, driveshafts, suspension arms, diff bearings etc etc. Had all of these, someimes multiple times.

However cooling fans still going at 140k unlike failed Taycan fans at 60k.

Same for AC and DC charger failures. Taycan v poor.

Heater is a solved problem though. Plenty of experience on that in the market but it's never just a hardware problem. It's a system problem.

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[whitex]

And I thought they had fixed the heater with a redesign a couple of years back, but obviously not.

Maybe they know what the proper fix it, but they are trying to save $20 a car, like they did with the PMC+/PMCC. It took them years to finally provide a cable with a temperature sensors - they tried everything else first, starting with just a bulletin, then warning sticker, then firmware update neutering the EVSE to half speed, eventually landing on the proper solution - replace everyone's cables (though even there they tied the replacement to a car VIN, not PMC+/PMCC serial number, so if you bought one not with the car, no fixed cable for you).

 

[whitex]

Sadly that depends on how good your validation programme is and the design of that depends on your experience with the underlying technology.

While I agree with this, years of failing heaters in production cars provide sufficient information that the heater design is bad. At that point, Porsche should spring for a specialist in the field of heaters to evaluate the proposed new solution by vendor, or perhaps suggest a better vendor with proven track record of making such parts.

 

[F1Ruaraidh]

While I agree with this, years of failing heaters in production cars provide sufficient information that the heater design is bad. At that point, Porsche should spring for a specialist in the field of heaters to evaluate the proposed new solution by vendor, or perhaps suggest a better vendor with proven track record of making such parts.

I would agree but I fear their arrogance is their failing and a lot of the solution is in the control software, not the hardware which is something the German outsourced model repeatedly fails at.

 

[whitex]

I would agree but I fear their arrogance is their failing and a lot of the solution is in the control software, not the hardware which is something the German outsourced model repeatedly fails at.

My suspicion is that now that they went IPO, the corporate bean-counters are making all the decisions, rather than engineers. Perhaps even engineers were replaced with lowest bidder contractors, or AI?

 

[prj]

I had a second recall to replace a still working (like the last one) heater module.
The fault I do have on my car with the heating has been no flow from vents which has now happened twice and reset itself but I don't really know how or why because nothing I tried to adjust worked then on both occasions it just went back to normal.
The first was in summer and it was just hot for a journey, the second was recently and the windows steamed up and it was cold.
It was back to normal again over the weekend.
I am not confident the service dept will be able to find an intermittent fault.

Get MapEV Diag yesterday, and scan the faults.
I am quite sure you will find an issue with the servomotors of the AC system. I had the same issues as you until finally there was only cold air coming out of a couple vents.
Two AC servomotors later it was fixed. Not a very big job.

I was thinking of replacing my wife's Audi with a Macan EV as the next car, but honestly, she would probably leave me if I got get into a car with Porsche reliability.

Just get the Ioniq 5 instead of the Macan. I had one back in 2021 and it's quite nice with the premium package.
The only thing that was a bit dodgy was the LKA, as it tended to bounce left to right a bit, but perhaps that's sorted now.

 

[f1eng]

Get MapEV Diag

Unfortunately I gave my PC away when I retired 16 years ago and haven't used one since.
Maybe one of my kids can get it!

 

[bn8959]

The original failure reason of the Webasto heater was fascinating. It was to do with NAND flash degredation that held the heater firmware. The chips were getting excessively hot which caused them to begin to ‘forget’ what they were storing. Normally NAND flash always degrades, but very slowly - this was accelerated by the heat. It could get to a point where the firmware was corrupted and the controller simply wouldn’t boot up. They released a software fix. Which was simply a matter of the controller periodically reflashing its own firmware - this write process ‘topped up’ the NAND so it wouldn’t fail!
Not sure now what the issue could be. Unless they are now reaching NAND rewrite limits!

 

[whitex]

Get MapEV Diag yesterday, and scan the faults.
I am quite sure you will find an issue with the servomotors of the AC system. I had the same issues as you until finally there was only cold air coming out of a couple vents.
Two AC servomotors later it was fixed. Not a very big job.

Thanks for the advice. I haven't ran your tool yet (real busy, all car projects on hold since the summer), but I have been meaning to check it out. That said, I did a quick scan with PIWIS3 and here are the errors that I thought were relevant:

Maybe you can help interpret. Given the history of HV heater, I presumed my heater died based on the first error, though the last one is more consistent with your theory. What do you think?

 

[whitex]

The original failure reason of the Webasto heater was fascinating. It was to do with NAND flash degredation that held the heater firmware. The chips were getting excessively hot which caused them to begin to ‘forget’ what they were storing. Normally NAND flash always degrades, but very slowly - this was accelerated by the heat. It could get to a point where the firmware was corrupted and the controller simply wouldn’t boot up. They released a software fix. Which was simply a matter of the controller periodically reflashing its own firmware - this write process ‘topped up’ the NAND so it wouldn’t fail!
Not sure now what the issue could be. Unless they are now reaching NAND rewrite limits!

Any respectable NAND part has a built in controller that takes care of the refresh (in addition to wear leveling, cache folding, etc). Of course this refresh can only be done when the part is powered on, so if someone was leaving not driving a car for a long time, or only ultra short trips, the chip would not have sufficient time to refresh itself. There are some dependencies as well, like writing at one extreme temperature and then storing at another extreme cause more decay, but I don't remember the specifics (last I worked with this was about a decade ago). This is why a lot of car ECUs boot from NOR first, then load NAND, but the NOR storage contains sufficient amount of code to be able to restore NAND from external source if needed. Apparently Webasto did not use this strategy (why they needed so much data stored that they couldn't fit all their code in NOR flash is probably another issue - code probably written by latest generation of programmers pulling in 50 dependencies from open source to write a "Hello World!" code).

 

[Scandinavian]

It's standard in all markets.

It's one of the many components of the heating system.

The heat pump was not standard here in France in 2020. I have no heat pump in my Turbo MY20

 

[Scandinavian]

Got an update from service, Porsche does not automatically approve heater replacement for any car that already had the heater replaced in the past (as they put it, it already has an "updated heater"). They require a full, multi-day dealer diagnostics visit, sending stuff to Germany, waiting them to get to looking at it between holidays, etc. Of course those appointments are not available on the spot, so for me it's more than couple of weeks before my car even starts this process. No loaners until then either. And of course, no remote diagnostics capability either.

It really makes me wonder, is Porsche process designed for deter customers from buying their cars for actual driving - they only want customers who use their cars just to look at them, but have other, reliable cars for driving (so I guess not a Porsche)? I was thinking of replacing my wife's Audi with a Macan EV as the next car, but honestly, she would probably leave me if I got get into a car with Porsche reliability. And I thought Tesla was bad with my early adopter experience, but in my decade of Tesla ownership they never left be without a car to drive for over 2 weeks, nor did any of my Teslas spend as much time at the shop as the Taycan. This is such a different experience than my 2001 911C4 I got in 2001 - that car ran with nothing but scheduled maintenance (except for tires, I used them up much faster).

Do you have the warranty, extended or original on your car? If so you should call Porsche Assistance.

When my heater pack in one April here in France, I was advised this was not safe to drive do to fogging and reduced visibility. Recommended to call Porsche Assistance and they collected the car. It also meant the will give priority for analysis and repair, plus I got a rental car FOC. Not a Porsche or any other luxury car but something that got us going. I think at that time we got a BMW 5 serie rental. Simple model but worked.

 

[Scandinavian]

It may not be the extreme conditions that kill it. I live in a fairly mild climate. Maybe in extreme conditions the heater gets sufficient cooling from the outside, but in mild climate it overheats and burns itself out?

Remember that the heater gets engaged nearly every time you drive the car, even in mild weather. It is engaged for battery heating when setting off in cooler temperatures as well as when preheating before HPC charging.

In car Scanner one can see how often the heter is engaged.

 

[whitex]

Do you have the warranty, extended or original on your car? If so you should call Porsche Assistance.

When my heater pack in one April here in France, I was advised this was not safe to drive do to fogging and reduced visibility. Recommended to call Porsche Assistance and they collected the car. It also meant the will give priority for analysis and repair, plus I got a rental car FOC. Not a Porsche or any other luxury car but something that got us going. I think at that time we got a BMW 5 serie rental. Simple model but worked.

Good to know. The car is still under original vehicle warranty. I already made other arrangements for transportation, but should that change, I might just try it.

 

[whitex]

Remember that the heater gets engaged nearly every time you drive the car, even in mild weather. It is engaged for battery heating when setting off in cooler temperatures as well as when preheating before HPC charging.

In car Scanner one can see how often the heter is engaged.

I know, I was thinking that Porsches testing might have missed the non-stress conditions, such as the heater running at a low duty cycle.

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