Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Power Conversion System (PCS) failure

This site may earn commission on affiliate links.

Concestor0

Member
Supporting Member
May 13, 2016
17
21
New Lowell
There are a few threads going here and on other forums for charging issues that turn out to be PCS failures. Most owners notice the failure when they are AC charging (Wall Charger or Mobile Connector). The charge rate will drop from 48A to 32A or 32A to 16A and give an error message saying "Charge rate reduced, Unplug and Retry".

Up to now all the PCS failures I've heard about on various forums have had the PCS replaced on warranty but today I was given an estimate of over $2,000 CDN to have mine replaced. The PCS is not covered under the battery warranty, just the basic 50,000 mile / 80,000km warranty. The PCS sits on top of the battery and controls AC and DC charging as well as supplying 12 VDC. It really should be part of the battery warranty.

The PCS has three 16A controllers, one operating gives you 16A, two operating gives you 32A and all three operating gives you your full 48A. If you are using a Wall Charger set up for 48A and one controller fails your rate is reduced to 32A and you get the reduced charge failure message. In my case I only have the Mobile Charger so when one controller fails I can still charge at 32A using the remaining two controllers, but I don't get a failure message until I have lost two out of the three controllers. By the time I lost two controllers I was outside the basic warranty.

I subscribe to TeslaFi and went back through my charge records and found abnormal charging started at 69,000 km and didn't show normal charging until 76,000km. Every AC charge during that interval showed the charge attempting to charge at 32A then failing to 16A, going back to 32A for a while then dropping back to 16A. It seems that one of the controllers eventually failed completely at 76,000km and then just used the remaining controllers to get to the Mobile Chargers max of 32A. And no error message for me to report.

If I had used a Wall Charger set to 48A just one time prior to my warranty expire I would have received the error message and had the PCS replaced under warranty as so many others have done.

I presented the TeslaFi data to Tesla clearly showing an abnormality and well within the warranty period but they refused to acknowledge it or even view it, they declared it non Tesla data. I asked them to retrieve their own data on the car and they said that they don't go back that far.

Does anyone have any experience or suggestions on appealing warranty claims? The service manager at the Vaughn Service Center (Toronto) had zero interest in discussing the complaint or assisting me in an appeal.

Help or suggestions would be greatly appreciated.
 

Attachments

  • Aug 2019 67800km last normal charge before failure.JPG
    Aug 2019 67800km last normal charge before failure.JPG
    239.1 KB · Views: 17,339
  • Aug 2019 69220km start of abnormal charging.JPG
    Aug 2019 69220km start of abnormal charging.JPG
    248.9 KB · Views: 832
  • Sept 2019 71770km sample abnormal charging.JPG
    Sept 2019 71770km sample abnormal charging.JPG
    253.7 KB · Views: 666
  • Oct 2019 76430km charging stays at 32A until second 16A controller fails.JPG
    Oct 2019 76430km charging stays at 32A until second 16A controller fails.JPG
    247.7 KB · Views: 787
Note to self plug into my friends new 40A circuit, Tesla Gen 3 Wall Connector, at about 45K miles/4 years and 6 months. I verified it would charge at 40A the other day. it would probably be best to charge at 48A for several hours over two charging sessions to verify proper functionality. I have read several posts on various forums where M3 owners have had this fail and replaced under warranty. I wonder if there could possibly be a design error or a bad lot of boards? or charging at the full 48A in very hot conditions causes premature failure? I feel you pain! Wish I had a good suggestion good luck.

Regards, Ron
 
Last edited:
  • Like
Reactions: Concestor0
The PCS is not covered under the battery warranty

What?

That is ludicrous. I can understand an argument that it's not part of the battery, but where are they drawing the line?! It is clearly "in" the "battery", as Tesla would claim accessing it would be accessing the battery. What else isn't "the battery" in there? Contactors? BMS? Coolant lines? The shell of the pack? In the warranty doc they define "Battery" as the "lithium-ion battery". That's either incredibly specific to the cells, or the common understanding of the entire pack including all electronics and internal connections IMO.

Parts of the PCS (maybe even the same parts) are even necessary for proper drive unit and battery function. It's such an integral part of their drivetrain/battery design, I don't know how they could possibly exclude it.

And no error message for me to report.

Ugh. This is the worst part. It seems like a good bit of engineering not to worry the owner about every little thing that goes wrong (especially when there's redundancy), but this clearly matters. Redundancy means something needs fixing, not ignoring until the redundant part fails.

Since they denied having logs themselves, I am not certain of this, but I think logs exist on the car too. I don't know if this is true or how to access them. Hopefully somebody else chimes in. All I can offer are condolences.


How far out of warranty are you?

EDIT: So, you probably don't want to go this route. But if you do, keeping in mind I'm not a lawyer, you might have some significant arguments as to what "the Battery" covers legally. I would entirely understand not wanting to go this route, unfortunately that's what Tesla hopes for.

EDIT2: The warranty says they replace the "Battery" with a suitable replacement at their discretion. This "Battery" they replace is indeed the entire HV Battery Pack with all components, PCS included. There is no way in hell the PCS isn't covered under that definition.
 
Last edited:
What?

That is ludicrous. I can understand an argument that it's not part of the battery, but where are they drawing the line?! It is clearly "in" the "battery", as Tesla would claim accessing it would be accessing the battery. What else isn't "the battery" in there? Contactors? BMS? Coolant lines? The shell of the pack? In the warranty doc they define "Battery" as the "lithium-ion battery". That's either incredibly specific to the cells, or the common understanding of the entire pack including all electronics and internal connections IMO.

Parts of the PCS (maybe even the same parts) are even necessary for proper drive unit and battery function. It's such an integral part of their drivetrain/battery design, I don't know how they could possibly exclude it.



Ugh. This is the worst part. It seems like a good bit of engineering not to worry the owner about every little thing that goes wrong (especially when there's redundancy), but this clearly matters. Redundancy means something needs fixing, not ignoring until the redundant part fails.

Since they denied having logs themselves, I am not certain of this, but I think logs exist on the car too. I don't know if this is true or how to access them. Hopefully somebody else chimes in. All I can offer are condolences.


How far out of warranty are you?

EDIT: So, you probably don't want to go this route. But if you do, keeping in mind I'm not a lawyer, you might have some significant arguments as to what "the Battery" covers legally. I would entirely understand not wanting to go this route, unfortunately that's what Tesla hopes for.

EDIT2: The warranty says they replace the "Battery" with a suitable replacement at their discretion. This "Battery" they replace is indeed the entire HV Battery Pack with all components, PCS included. There is no way in hell the PCS isn't covered under that definition.


I totally agree every component in the penthouse should be considered as part of the HV battery and have an 8 year/120K mile warranty (for the long range models) to back it up.
 
I am sorry to hear this OP. Hopefully your bringing up "Teslafi" didnt automatically preclude the service center from helping you. They are not interested at all in hearing about ANY "statistics / data etc" from ANY monitoring that is not tesla, so tend to completely shut down the second someone mentions it.

As to the specific topic, I find it a bit strange, since a member of this board that appears to be a tesla insider and posts occasionally (although I dont know what position in tesla) mentioned that the PCS should be included in the battery warranty. See specific quote below:


PCS should be included in battery warranty. Most likely new PCS will only be covered for balance of battery warranty going forward.


I would ask the service center again, why the PCS is not covered under the battery warranty, since its connected to it, and can they please show you where in the warranty information it shows this is not covered, or can they escalate this to be covered / where is the contact information for you to escalate"

That is what I would do.
 
I totally agree every component in the penthouse should be considered as part of the HV battery and have an 8 year/120K mile warranty (for the long range models) to back it up.

For the benefit of both sides, I could make the argument that not all components should be covered. For example, the pyro fuse is clearly a "wear" component (or, at least designed to self-destruct) yet is within the penthouse. Actually, that's the only component I can make a clear argument for exclusion.

The PCS may be considered charging equipment and might normally be outside this consideration, but it is a bit more than that for Model 3. Admittedly, it's the battery pack part that's probably in the gray area the most.

They are not interested at all in hearing about ANY "statistics / data etc" from ANY monitoring that is not tesla, so tend to completely shut down the second someone mentions it.

This is actually a really good point, and why I've been struggling to finish/release my app. Tesla clearly shouldn't be held responsible for third-party representations of their data, however accurate it may be. Never bring up TeslaFi, ScanMyTesla, etc. when dealing with Service - always portray info you can tell via the car or app alone (e.g. "I've seen the charge rate drop to 16A intermittently"). Good lesson for everyone here, especially since TeslaFi isn't recording anything that the app/car doesn't already show in some way.
 
I am sorry to hear this OP. Hopefully your bringing up "Teslafi" didnt automatically preclude the service center from helping you. They are not interested at all in hearing about ANY "statistics / data etc" from ANY monitoring that is not tesla, so tend to completely shut down the second someone mentions it.

One of the reasons we use services like TeslaFi is to document what is happening with our cars, we own the cars and this is our right. If Tesla chooses not to document certain parts of our cars history or operation then this should not preclude owners from recording this info as evidence of normal or abnormal operation.

As to the specific topic, I find it a bit strange, since a member of this board that appears to be a tesla insider and posts occasionally (although I dont know what position in tesla) mentioned that the PCS should be included in the battery warranty. See specific quote below:

I would ask the service center again, why the PCS is not covered under the battery warranty, since its connected to it, and can they please show you where in the warranty information it shows this is not covered, or can they escalate this to be covered / where is the contact information for you to escalate"

I have only spoken to the one person who identified himself as being the manager of the Vaughn Service Center and he offered no one else to talk to other than the roadside service number. He shut me down completely and offered no help in identifying when the original 16A controller might have failed. I can understand him not wanting to be responsible for a difficult warranty decision but he could at least identify who could.
 
This is actually a really good point, and why I've been struggling to finish/release my app. Tesla clearly shouldn't be held responsible for third-party representations of their data, however accurate it may be. Never bring up TeslaFi, ScanMyTesla, etc. when dealing with Service - always portray info you can tell via the car or app alone (e.g. "I've seen the charge rate drop to 16A intermittently"). Good lesson for everyone here, especially since TeslaFi isn't recording anything that the app/car doesn't already show in some way.

I would be interested in what a judge would say about Tesla denying claims because an owner is electronically monitoring/recording what there car is doing. It's also a bit much to ask that an owner sit and monitor their charging. There are certain charging malfunctions that trigger an alert but not all, such as mine. I went a full month with abnormal indications without me knowing.
 
I would be interested in what a judge would say about Tesla denying claims because an owner is electronically monitoring/recording what there car is doing. It's also a bit much to ask that an owner sit and monitor their charging. There are certain charging malfunctions that trigger an alert but not all, such as mine. I went a full month with abnormal indications without me knowing.

Sorry I dont agree. You are free to monitor your device as how you see fit, but tesla is not obligated in any way, shape or form to acknowledge the authenticity of said monitoring.

Translation, you are free to monitor with whatever, but tesla is under zero (less than zero) obligation to do anything based on your monitoring of non official tools.

One should NEVER EVER mention any third party tool to tesla when reporting a problem, hard stop.

EDIT... let me say that I dont think tesla would deny a claim based on that. They are just not interested in the slightest (or obligated in the slightest) to accept data from any third party monitoring tool as "proof" of anything.

Slight distinction. Thats not denying a claim because you used third party monitoring, its "not accepting any data outside of their own as proof of anything".

In general they hear so many people say "Teslafi shows my car has 6 less miles than it should, and also shows that blah blah blah blah!!!" that the minute someone mentions it, all consideration for anything the person is saying likely goes in one ear and out the other.

Back on topic, I still am wondering how this is not covered. I am just wondering if you started with "I noticed strange charging abnormalities on my screen when I was charging, but got no error messages" you would be getting farther than "Here is this teslafi data!"

Sucks for sure, and I am speculating, but one thing I know for a fact is that one should never ever mention third party tools to any manufacturer when talking about an issue with their car (not just tesla).
 
Last edited:
Fully agree with @jjrandorin said, basically took the words out of my mouth.

In more on-topic discussion, I debated this all with my wife. Tesla would have a strong argument that the PCS is "charging equipment". Unlike gas drivetrain warranties that are well-understood and legally established, there's a lot of legal clarification needed going forward with EVs. For example, if this was a sealed pack without the serviceable "penthouse", would that alone mean the PCS is indeed part of the "battery"? But then what about the series connection that occurs inside the penthouse, which is absolutely part of the "battery"? Thrilling debate topic. For me. :p

One of the reasons we use services like TeslaFi is to document what is happening with our cars, we own the cars and this is our right. If Tesla chooses not to document certain parts of our cars history or operation then this should not preclude owners from recording this info as evidence of normal or abnormal operation.

TeslaFi is not your right. TeslaFi's use of the Tesla API is not their right. TeslaFi's interpretation of the data from the Tesla API to provide you a service is not your right. TeslaFi cannot make any legal assertion that their data is accurate (it is, in fact, riddled with confounding factors not conducive to discussing warranty issues). And as the writer of an app that also provides info (though via the CAN bus, not the API), I can tell you there's no way in hell I support my users presenting the data to Tesla in the context of a warranty claim. Knowing the data a bit deeper, I can see Tesla's side that you could imply a number of incorrect things from TeslaFi data (see: every thread on degradation where the cause was cold temperatures). Even with the charging data, it could have been something like charge equipment/port temperature causing it to throttle back and not PCS failure (you can't tell with just the data you showed). Clearly, since they're replacing it, there is a PCS problem but that's not necessarily what the data shows.

I understand your perspective. It is incredibly frustrating that all you have to support your claim is historical third-party data - you didn't have much of a choice in this regard. But for your argument to succeed you much assert that TeslaFi's representation of the data is correct and without fault, which is absolutely isn't true, nor do they want that to be true. Additionally and very interestingly, I have never succeeded with a warranty claim for any manufacturer based on historical anecdote.

EDIT: I should clarify that the Tesla API (which TeslaFi uses) is an unofficial, freely provided service.
 
Last edited:
Thanks everyone for your thoughts and suggestions.

Here is a summary of the factors at hand:

1. I was hoping to get better support from Tesla to fully understand a very significant and expense issue with their product.
2. Because I use a Mobile Charger two of the 16A controllers needed to fail for Tesla and myself to recognize that the PCS had failed. There are many reports of PCS units being replaced under warranty because of one of the 16A controllers has failed and the owner could only charge at 32A.
3. Tesla cannot determine if the first 16A controller failed before or after the warranty period therefore they are assuming that it failed after the warranty expired despite plenty of evidence that they fail much earlier. The evidence that TeslaFi shows of a failure at 67,000km may not be at as high a standard as what they could have collected on their own but it is good evidence and does match the voltage, amperage etc... that is observed in real time in the car.
4. Having an adversarial relationship with Tesla is very uncomfortable for me, I was among the first Model 3 owners in Canada. I waited two years for may car. I'm an early shareholder. Now Tesla is declaring that I can't prove that the initial failure happened during the warranty period (as happened to everyone else that I'm aware of) - therefore give us more of your money.
5. The PCS is a multi-function unit, AC, DC and 12 volt control, if any of those functions fail the entire PCS needs replacing. It's going to be a great revenue stream for Tesla in the future as our cars age.
 
Some day Tesla is going to have to let third parties including owners work on their own cars (especially after the warranty has expired). Yes even the HV systems, I KNOW IT IS DANGEROUS. Tesla should not be held liable for untrained non-Tesla people attempting to work on high voltage systems. Maybe in the future owners or third party repair shops will be able to purchase refurbished PCS boards and return the bad board as a core to be repaired for the next customer, that is assuming it is repairable. Unfortunately, having a single board perform multiple functions has its pluses and minuses.
 
  • Like
Reactions: Concestor0
Thanks everyone for your thoughts and suggestions.

Here is a summary of the factors at hand:

1. I was hoping to get better support from Tesla to fully understand a very significant and expense issue with their product.
2. Because I use a Mobile Charger two of the 16A controllers needed to fail for Tesla and myself to recognize that the PCS had failed. There are many reports of PCS units being replaced under warranty because of one of the 16A controllers has failed and the owner could only charge at 32A.
3. Tesla cannot determine if the first 16A controller failed before or after the warranty period therefore they are assuming that it failed after the warranty expired despite plenty of evidence that they fail much earlier. The evidence that TeslaFi shows of a failure at 67,000km may not be at as high a standard as what they could have collected on their own but it is good evidence and does match the voltage, amperage etc... that is observed in real time in the car.
4. Having an adversarial relationship with Tesla is very uncomfortable for me, I was among the first Model 3 owners in Canada. I waited two years for may car. I'm an early shareholder. Now Tesla is declaring that I can't prove that the initial failure happened during the warranty period (as happened to everyone else that I'm aware of) - therefore give us more of your money.
5. The PCS is a multi-function unit, AC, DC and 12 volt control, if any of those functions fail the entire PCS needs replacing. It's going to be a great revenue stream for Tesla in the future as our cars age.

Upon thinking about it some more, I don't know if the TeslaFi graphs necessarily show what you're thinking regarding the PCS failure.

Some others on here have similar graphs, but are also logging the "pilot current". To my knowledge, this is the current the external charging equipment is saying it will support (whether that's the mobile connector or a public station, etc.). This has dropped in a similar pattern (even in the 16A jumps), presumably due to a heat issue and it's throttling occasionally to prevent overheating. In these cases, there was nothing wrong with the PCS, yet the graph looks very similar.

So no, that graph alone doesn't necessarily, without a doubt, show that the PCS was failing prior to 80,000km. There's everyday normal reasons it might look like that, especially if it happened in accordance with warmer temperatures.

I would maybe get in touch with others on this forum that have had the PCS replaced under warranty and ask for their docs. They should state which warranty there were covered under (the battery/drive unit warranty or the other limited warranty). If none of them were under the battery/drive warranty... well, yeah, that's gonna suck.
 
Upon thinking about it some more, I don't know if the TeslaFi graphs necessarily show what you're thinking regarding the PCS failure.

Some others on here have similar graphs, but are also logging the "pilot current". To my knowledge, this is the current the external charging equipment is saying it will support (whether that's the mobile connector or a public station, etc.). This has dropped in a similar pattern (even in the 16A jumps), presumably due to a heat issue and it's throttling occasionally to prevent overheating. In these cases, there was nothing wrong with the PCS, yet the graph looks very similar.

So no, that graph alone doesn't necessarily, without a doubt, show that the PCS was failing prior to 80,000km. There's everyday normal reasons it might look like that, especially if it happened in accordance with warmer temperatures.

I would maybe get in touch with others on this forum that have had the PCS replaced under warranty and ask for their docs. They should state which warranty there were covered under (the battery/drive unit warranty or the other limited warranty). If none of them were under the battery/drive warranty... well, yeah, that's gonna suck.

The fluctuations were likely not heat related, it was mostly Sept in Canada and the outside air temp was showing ~70 f or less in my garage, charging overnight for low power rates. Also it only happened for that short time period over the two years I've had the car. That being said it would be great if other people with monitoring apps could see if post any similar behavior.

If nothing else comes out of this thread I would at least hope that other owners will know to carefully monitor their home charging and report abnormalities to Tesla prior to there basic warranty expiration.
 
I'm starting to get more information from people who have had PCS failures, still no one else who has been denied warranty. Another southern Ontario owner posted this pic of his service record showing PCS replacement after his basic warranty had expired (90,000km) and you can see that it was covered under the Battery warranty. This was a different service center than the one I went to in the Toronto area.
 

Attachments

  • FB_IMG_1595033146209.jpg
    FB_IMG_1595033146209.jpg
    13.1 KB · Views: 1,020
  • Informative
Reactions: swaltner
I'm starting to get more information from people who have had PCS failures, still no one else who has been denied warranty. Another southern Ontario owner posted this pic of his service record showing PCS replacement after his basic warranty had expired (90,000km) and you can see that it was covered under the Battery warranty. This was a different service center than the one I went to in the Toronto area.

Maybe go to a different service center (and hope your current one has not put all sorts of notes in there), and talk to them about it, and dont mention anything about teslafi or anything else thats third party monitoring. Say "I noticed I had abormal charging fluctuations around this time, as shown on my in car display".

I still maintain that your mistake was trying to bring the service center "your teslafi data" as proof that something needed to be fixed.
 
PCS / chargers have never been covered under the S/X battery warranty, and I don’t think you’re going to have much luck stating the physical location of those components on the 3/Y makes them subject to the battery warranty.

Drive unit warranty doesn’t cover half shafts just because they’re physically connected to the drive unit. Same sort of issue.

Sounds like maybe they’ve repaired a few under that warranty in the past, but their tune appears to have changed. Probably because they’re realizing the failure rate is higher than they want to be on the hook for and have run out of good will for early owners.
 
I'm starting to get more information from people who have had PCS failures, still no one else who has been denied warranty. Another southern Ontario owner posted this pic of his service record showing PCS replacement after his basic warranty had expired (90,000km) and you can see that it was covered under the Battery warranty. This was a different service center than the one I went to in the Toronto area.

Did you ever get resolution on this? I am at 56k miles and get 0 amps while AC charging. Service scheduled for Wednesday. They reached out today and informed me it’s most likely the PCS, isn’t covered under warranty and will cost me $1500 USD... I’ve asked to see some documentation on how it’s not covered as part of the battery/drive unit warranty. To me it’s akin to the inverter on the motor failing and saying that it’s not part of the motor warranty. What else in inside this penthouse that can cost me thousands?

To add, I have a coworker who just ordered a Model 3. I told him I’ve only had an amazing experience so far but I’m sure this will scare him away. He keeps his cars for 10+ years and his main concern was the battery warranty. Before today I would’ve told him (apparently incorrectly) everything in the penthouse was covered.
 
Did you ever get resolution on this? I am at 56k miles and get 0 amps while AC charging. Service scheduled for Wednesday. They reached out today and informed me it’s most likely the PCS, isn’t covered under warranty and will cost me $1500 USD... I’ve asked to see some documentation on how it’s not covered as part of the battery/drive unit warranty. To me it’s akin to the inverter on the motor failing and saying that it’s not part of the motor warranty. What else in inside this penthouse that can cost me thousands?

To add, I have a coworker who just ordered a Model 3. I told him I’ve only had an amazing experience so far but I’m sure this will scare him away. He keeps his cars for 10+ years and his main concern was the battery warranty. Before today I would’ve told him (apparently incorrectly) everything in the penthouse was covered.

Battery warranty covers the battery. Not the charging system. Where the component is physically located is fully inconsequential. The documentation you’re looking for is the warranty doc itself, which says it covers the “battery”, not “everything that happens to be located in the same arbitrary sheet metal enclosure as the battery”.

Your inverter analogy is not appropriate because the inverter is an integrated drive unit component that is required for the drive unit itself to function. A better analogy would be half shafts, which are not covered under the drive unit warranty despite being physically bolted to the drive unit.

As you’ve no doubt noted, your high voltage battery is working fine, even with a failed PCS.

Sorry about the repair. That’s a bummer.
 
Did you ever get resolution on this? I am at 56k miles and get 0 amps while AC charging. Service scheduled for Wednesday. They reached out today and informed me it’s most likely the PCS, isn’t covered under warranty and will cost me $1500 USD... I’ve asked to see some documentation on how it’s not covered as part of the battery/drive unit warranty. To me it’s akin to the inverter on the motor failing and saying that it’s not part of the motor warranty. What else in inside this penthouse that can cost me thousands?

To add, I have a coworker who just ordered a Model 3. I told him I’ve only had an amazing experience so far but I’m sure this will scare him away. He keeps his cars for 10+ years and his main concern was the battery warranty. Before today I would’ve told him (apparently incorrectly) everything in the penthouse was covered.

If his main concern is the battery, and its (currently 15k+ ) cost to repair, then he should be fine with this. 1500 isnt 15k, and while these cars have fewer moving parts than an equivalent ICE vehicle, there isnt any promise of NO repairs. If your friend keeps cars 10+ years, then its highly likely they have had to pay for repairs outside of warranty before, and possibly expensive things.

Your friend likely would not even understand what "everything in the penthouse" means, because the term "penthouse" related to cars is not a standard term. You had a part connected to your battery that is failing, not the battery, and its going to cost 1500 to replace, you dont have to replace the battery.

It sucks, I am not saying it doesnt, but for your friend that keeps cars 10+ years, there shouldnt be any additional concerns.