daveo4EV

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wonder if they can fix this with an OTA update like Tesla did when a similar problem was found with the Model 3…
 

legataycan

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I too have suffered with this same issue, when I took the car to Porsche they claimed they had not heard of this problem before.

It's rather terrifying. Sadly I'm in the UK so cannot contribute to this NHTSA complaint.
 


fullmetalbaal

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I'm glad there's a complaint. Maybe Porsche will actually look into it.

I've witnessed a few times that the brakes didn't engage nearly as much as expected and I had a distinct "long pedal feel" followed by a panicky slamming of the brakes. Always happened to me during conservative driving early in the morning, in the cold and wet (ie when the car is 'cold soaked'). Not very reproducible, I'd say it happens about once a month when driving daily here in the PNW winter.

The reason that I'm not running to get it fixed is simple: the only thing I get from dealers is "well, we've never heard of this before" and "when we drive the car around the block it works fine".

I've had it happen often enough, and I've heard others report it frequently enough that I believe it to be real. If I had to guess, under some circumstances the car thinks it's getting enough regen braking so it doesn't "boost" the conventional braking, but in these situations regen braking actually isn't doing enough to slow down the car (bc of the cold). Then when it does pull in enough 'conventional braking' the disks are wet/cold/rusted and take a split second to get up to temp.

IIRC Tesla also faced an issue where the auto-regen braking in some cold conditions had unexpectedly weaker braking. I wouldn't be surprised if this is the kind of stuff all the different companies need to work through as they launch their EVs. Where Porsche is different from Tesla is that Tesla has the actual brake pedal always skip past regen into normal braking, so Tesla avoids the "oh shit" feeling when the actual brake pedal seems to be too weak.
 

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Porsche does a great job cooling their brakes. It’s also a good idea to give them a tap in the cold and wet.

With a Taycan, that’s a little trickier as so much of it is regen.
 


Raphie

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I had this pressureless braking now a couple of times, the resistance on the pedal is lower, but repressing with your foot (pump) puts the pressure back on immediately. It’s, at least what I’ve experienced, not sustaining and have experienced similar behavior in other cars.
 
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Tooney

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I'm trying to understand the circumstances here. What is happening in wet/cold conditions:
--regen braking fails?
--regen braking works but mechanical brake is not applied strongly or quickly enough?
--regen braking works but tires slip on wet road so more mechanical braking is needed?
I understand that mechanical braking can be impeded by wet brake disks/pads, but I don't understand how wet/cold is affecting regen braking, which is what the complaint seems to imply.
 

xyeahtony

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I'm trying to understand the circumstances here. What is happening in wet/cold conditions:
--regen braking fails?
--regen braking works but mechanical brake is not applied strongly or quickly enough?
--regen braking works but tires slip on wet road so more mechanical braking is needed?
I understand that mechanical braking can be impeded by wet brake disks/pads, but I don't understand how wet/cold is affecting regen braking, which is what the complaint seems to imply.
As someone who works in customer service, i always take complaints at face value when theyre typed in ALL CAPS
 

Windpower

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I'm trying to understand the circumstances here. What is happening in wet/cold conditions:
--regen braking fails?
--regen braking works but mechanical brake is not applied strongly or quickly enough?
--regen braking works but tires slip on wet road so more mechanical braking is needed?
I understand that mechanical braking can be impeded by wet brake disks/pads, but I don't understand how wet/cold is affecting regen braking, which is what the complaint seems to imply.
While I personally have not experienced this brake failure, I feel the pain of anyone who has.

I think what's happening is this: at certain times of the day (the first drive of the day), Porsche turns off regen braking and instead uses 100% mechanical brakes. It does this to 'bed'' the mechanical brake to remove any corrosion. If the mechanical brake fails while in this mode, there is no regen to take some of the load off of the mechanical brakes, and you can feel the car not slowing. If regen were working, then it would take most of the brake load and even if the mechanical brakes were failing, you probably wouldn't notice.

I think this has nothing to do with regenerative braking: I think this is probably a software bug (the car gets confused and does not apply the mechanical brake correctly).

This is pure speculation on my part.
 

Dee

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If you didn't get the collision warning you were not going to hit anything anyway.

It is known that wet brakes don't brake that well, ALL cars do that.
A Taycan is a heavyweight so it'll occur more noticable.
Besides, I don't think this dramaqueen needs to tell Porsche how to design brake systems.

I just don't buy it.
If this was the case, many Taycans would have been affected imho.
This guy is just an idiot.
 
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MyA

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My dash of salt.
I think it happens to ALL taycans that happen to live in cold, wet, conditions at first braking occasion. I have felt it numerous times.

After the first braking, all is good.

The car has to be standing for a certain period of time, in the cold and in wet/snow conditions. And only the 1st braking is “different”

As my 1st stop is usually down the block, in my quiet neighbourhood, it is NOT a dramatic issue. I just break harder and tell myself: well, this is how it is designed… No fuss

WOuld it be much different if my 1st braking occasion was at higher speeds?
Maybe.
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