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HV Battery replaced and now the Drive Unit! (out of warranty)

(Another HV battery replacement thread)

My 2013 Model S was working just fine, then suddenly started throwing error codes. I let it sit for about 5 days looking for options. Ultimately I decided to take it in before my appointment to ask for them to help with diagnosing the messages or clearing them so I could continue to drive the vehicle. As I approached the service center, maybe 30ft from the entrance the vehicle completely shut down and that was that.

I was given the new battery replacement option but I pressed them to "look" for a cheaper alternative. The parts catalog seems to default to showing what is in-stock and available. The re-manufactured packs where listed so they called the service department and where told they are around $10,500. I said that is what I wanted. Thanks to other forum members I confirmed that HV batteries replaced at the owners expense have a 4yr or 50000 mile warranty.

I had to leave the car sitting in their lot for over a week before my official service appointment came up. Then they ordered the re-manufactured 75kwh pack and I was told it could take 10 weeks. However just this Friday (after 4 weeks) they got the back and plugged it into the vehicle and told me they needed to run diagnostics and test drive the vehicle on Monday before releasing it.

I just got a message this morning that during the test drive they got more error codes, this time from the drive unit and the rear drive unit might need replacement!!!! They said they are getting the message about reduced power.

It is very suspicious that a functioning battery and a rear drive unit would simultaneously fail. Did they replace the HV battery when the rear drive unit was the culprit? Was there a recent software update (including firmware) that triggered these faults and shut the system down where previous versions it would have been considered fine?

I don't want to be a conspiracy theorist, but I still remember when my MCU1 was blacking out and their first diagnosis said it was caused by the 3G modem so they upgraded it to a 4G modem. Obviously that didn't fix it and it kept randomly crashing so they replaced the whole unit and told me it was the power supply for the display. I questioned them on how a faulty power supply could some times work perfect and other times not and how when it was out the climate control didn't work. Anyway after going round and round they replaced the MCU and eventually we found out it was simply the media card that was causing the crashes.
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
6,006
13,810
Hickory, NC, USA
Summoning @wk057 to the thread! :)
👋🏻

Without knowing the exact errors originally presented, hard to say what the issue could be.

It's definitely possible the drive unit had an isolation issue that the BMS was reporting. (These usually present as "soft" errors during a drive, things like "Car may not restart"). The 2013 S's, especially early 2013's, are a bit of a mixed bag though.

The vehicle actually shutting down out of the blue would seem to indicate an actual battery issue. Things like a DU isolation issue wouldn't cause a shutdown, just a failure of the car to restart after parking and a shutdown of the HV system at that time.

Guessing you had a 60 pack (based on the replacement being a 75 and your signature saying 40), and the early 60 packs are even more of a mixed bag. Also, as an older 60, you probably had a pretty old revision drive unit (unless replaced at some point after mid 2015)... and those have known issues as well.

Without knowing more, I'd guess a combination of failures is possible.
 
👋🏻

Without knowing the exact errors originally presented, hard to say what the issue could be.

It's definitely possible the drive unit had an isolation issue that the BMS was reporting. (These usually present as "soft" errors during a drive, things like "Car may not restart"). The 2013 S's, especially early 2013's, are a bit of a mixed bag though.

The vehicle actually shutting down out of the blue would seem to indicate an actual battery issue. Things like a DU isolation issue wouldn't cause a shutdown, just a failure of the car to restart after parking and a shutdown of the HV system at that time.

Guessing you had a 60 pack (based on the replacement being a 75 and your signature saying 40), and the early 60 packs are even more of a mixed bag. Also, as an older 60, you probably had a pretty old revision drive unit (unless replaced at some point after mid 2015)... and those have known issues as well.

Without knowing more, I'd guess a combination of failures is possible.
The car shutdown when I was in park waiting at the service entrance queue.

Also under warranty the rear drive was replaced but it was quite a while ago and who knows what I got in exchange. I don’t remember if the replacement was because of noise, thunks or electrical.

In their most recent message they describe the drive unit failure as mechanical. How would that show up as an error code and the vehicle seem totally fine except for the reduced power output?
 
Attaching pictures of error code several days before and day of shutdown.

After the vehicle went dark we had to use a booster battery to wake it up and get it into tow mode. Several days later I came back to the vehicle and woke it up again and wanted to grab some diagnostics from the CAN bus, had to make the OBD2 to CAN adapter for my reader. While trying to get the HV battery data the car drained my booster battery and shutdown again. I gave up at that point. The 3rd image is from Tes⸱LAX
 

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They just messaged me and said it is a DU Isolation.

So some insulation breaks down over time, or perhaps AC leakage, and they are measuring this?

I am an electrical engineer that works on battery and brushless motor drives and would love to see some explanation of this.

Still two somewhat independent systems failing together 🧐
 
Yeah the errors you posts are all referencing external isolation problems and not necessarily a problem with the battery pack.

Most likely the drive unit was always the culprit.
Thanks for all the information and honesty you bring to the forum. When I was making a decision on the repair I saw the transportation to and from a 3rd party as a lost cost. Going it fairly blind these failures and repairs really suck.
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
6,006
13,810
Hickory, NC, USA
When I was making a decision on the repair I saw the transportation to and from a 3rd party as a lost cost. Going it fairly blind these failures and repairs really suck.
We've been spitballing and kind of randomly testing different approaches to this issue, since we realize saying "Well, you're going to have to pay $X immediately just to get the car to us" is not appealing.

But, in our 6+ years working on the Model S and other Tesla vehicles, we've had effectively zero customers decide not to follow through with service once we get their car, present them with the facts, and our most cost effective options to resolve them. I can count on one hand how many times customers have been like, "Nevermind, I'll take the car to Tesla instead" or another avenue of not wanting service with us.

With that in mind, we're trying to figure options that are more palatable to the customer. One such alternative is with us arranging transport of the vehicle to us upfront, diagnosing, and presenting the most cost effective options, and us just absorbing the real transport costs as part of those options' cost. Should the customer decide not to go with any of those, we'd charge a diagnostic cost (that likely doesn't cover transport), and it'd be up to the customer to retrieve or pay for transport of their vehicle. If they go with one of our options, the cost to get the car to us is handled, and we'd work with them on what's best for getting it back (over half generally come pickup and drive their vehicles away after repairs).

While looking at the whole picture that may not seem like a win, I think it helps give the customer a bit more confidence overall. Like, we're going to get your car transported from across the country because we're sufficiently convinced that you still won't find a better option than us for your service.

And at the end of the day, I know that depending on what the exact issue is, we may not be the best option... and I've gotten a few customer vehicles in, presented them with our options, and then noted that it'd be in their best interest to just let us trailer the car down to Tesla Service in Charlotte to handle their issue because they had a slightly better option at the time. Surprisingly, have only actually had a customer go that route once, with the remainder being so surprised that we'd even suggest it that they went with us anyway.

Edit: Another option we tend to offer customers in for relatively expensive services is just a buyout option. Don't want to pay to fix the car, we'll offer you $X for the title to it, as-is where-is. And we've actually had more people than anticipated just go with that route. The last customer to do so, from TX, was like, "Wait... you'll give me $X for a broken car? Well that's a no-brainer, I'll take it and just go put that down on a Plaid." :cool:
 
There have been a lot of messages back and forth with the service representative where I felt like I had to guide them through the repair process. I kept asking them to diagnose the root of the faults and stop "swapping" parts.

They replaced the rear drive unit because of the DU Isolation problem and ultimately swapped by original HV battery back in the vehicle. Then they said that they fixed an issue with the battery with a "software update". They instructed me to drive the vehicle and cycle the battery and the BMS will be adjusting the capacity over the next few weeks.

To bad I will never know what really happened or what the root cause of any of this is. Why the drive units develop isolation faults and how much it would really cost to repair. I was sold a re-manufactured drive unit for $4800 and they probably will take my drive unit, clean it up and repair the isolation fault with only a few hours labor and sell it to someone else.

My total repair bill went from around $13,000 down to $6,000 so half but still expensive compared to any traditional automobile.

Now I hope the battery holds up for a few more years.
 
  • Informative
Reactions: kavyboy

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
6,006
13,810
Hickory, NC, USA
Glad they at least back tracked on the battery being at fault.

Then they said that they fixed an issue with the battery with a "software update". They instructed me to drive the vehicle and cycle the battery and the BMS will be adjusting the capacity over the next few weeks.

This sounds like the original pack has the brick6 sense issue and the BMS is learning how to correct for that missing sense line.

I'm glad they have a workaround for this, mainly for folks out of warranty, but in-warranty I think they should be replacing batteries that have the brick6 issue.
 
Thanks for this information! I'm prepared if my pack is done but it's awesome to know that it might be a glitch. At 100k+ miles I'm tempted to upgrade from 85 on my 2014 (if possible) so I'm not stranded and waiting.
Hmmmm, can you do that? Power electronics and drive unit(s) are different, and advertised different top speeds means likely different final drive? Might be more hassle than helpful.
 
I just posted yesterday of the same story about the HV battery and DU on my 2012 Model S 85:

Good thing Tesla was able to reverse course and install original battery when indeed the DU was bad. You came out ahead as I did replace my battery for 5k (3rd party) then went back to Tesla for the DU replacement for 6k. I think this issue is becoming more common for out of warranty large rear drive units on the model s.
 
If anyone ever gets the REAL truth from a service center please let me know. Now we get Montreal call center not Draper. Lady tells me "" I just take calls, I have zero technical knowledge"" . How nice. My car died on Friday, she said drive it on interstate 40 miles, don't worry. Idiot. I emailed SC , no reply. Have appointment next Friday. Service has deteriorated to horrible. Our SC has six bays for over 100k cars in the area. We will see next Friday what they say is wrong with my pack?
 
If anyone ever gets the REAL truth from a service center please let me know. Now we get Montreal call center not Draper. Lady tells me "" I just take calls, I have zero technical knowledge"" . How nice. My car died on Friday, she said drive it on interstate 40 miles, don't worry. Idiot. I emailed SC , no reply. Have appointment next Friday. Service has deteriorated to horrible. Our SC has six bays for over 100k cars in the area. We will see next Friday what they say is wrong with my pack?

So far my vehicle is at least functional but I still have doubts about it's long term reliability and I really had to push back on the service center based on what brief information and background I was able to dig up from this forum.

Also the only communication they would process was messages through the app and with that only 1 or maybe 2 exchanges per day. When I scheduled my appointment it was around 2 weeks out, they wouldn't touch the car or communicate until that appointment time came around. If I was not patient and in a rush they would have just replaced everything necessary and pushed the car out the door. The told me a few times that the tech was going to work late to get time for my car. I live in the California Bay Area and there are a lot of Teslas here!

So yes there is a big question in my mind, and a discussion for another thread, but how can Tesla sell a million cars a year with this kind of service problem?
(Don't respond here, feel free to start a different thread)
 

tesluv108

2013 p85 2020 P3D 2016 p90d
Aug 29, 2020
43
10
Ohio
Yeah the errors you posts are all referencing external isolation problems and not necessarily a problem with the battery pack.

Most likely the drive unit was always the culprit.
Have you ever heard of or personally see a drive unit failing with under 5,000 miles? I have a 11/2015 P90D non-ludicrous. Basically throwing all the codes attached and lost most power today and all regen. Car doesn’t have issues charging
09709C9D-85E7-4401-9990-9A0729B51C8F.jpeg
 

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