2015 base model s - Out of warranty $14k service quote

[Bryannearatl]

Hi all, I need advice. I have a 2015 base model s, vehicle had no issues, codes or odd noises at the time of the most recent update. I did the update and on the next drive the vehicle failed. Tons of BMS error codes. Replaced 12v battery issues unchanged. Towed to service center and here is what I am being told:
1. Low isolation found in rear drive unit $7k
2. Pack contactors opened under load $5k
3. Low isolation in A/C compressor $1k

Here is my question as ignorant as it may be. Is there a chance that there is no issue beyond the contactors? It seems very odd that both the rear drive unit and the A/C compressor have issues out of nowhere. Does anyone have experience with these issues?

Thanks for any help!

 

[mongo]

Hi all, I need advice. I have a 2015 base model s, vehicle had no issues, codes or odd noises at the time of the most recent update. I did the update and on the next drive the vehicle failed. Tons of BMS error codes. Replaced 12v battery issues unchanged. Towed to service center and here is what I am being told:
1. Low isolation found in rear drive unit $7k
2. Pack contactors opened under load $5k
3. Low isolation in A/C compressor $1k

Here is my question as ignorant as it may be. Is there a chance that there is no issue beyond the contactors? It seems very odd that both the rear drive unit and the A/C compressor have issues out of nowhere. Does anyone have experience with these issues?

Thanks for any help!

@wk057 may weigh in.
It could be problems 1&3 existed for a while but only recently worsened to the point where the car threw an error and opened the contactors while under load (item 2). They both sit on the HV bus and can only be isolated for individual testing by disconnecting them.

Doubtful the issue is only the contactors.

 

[Bryannearatl]

Thanks for the response. I do recall a couple weeks before this happened the A/C would not blow from the front vents, it cooled fine from floor of dash vents so I didn't thing much of it. It seemed to correct itself. I cant throw $14k into this vehicle so I am considering taking to a 3rd party shop (if I can find 1) or do what I can myself, historically I do all my own vehicle repairs but of course this is more of a computer with a bomb in it.

Before making this decision I'm curious if I should have Tesla replace the AC compressor to see if that allows the contactors to close. Any thoughts on this or better ideas?

Thanks again.

 

[mongo]

Thanks for the response. I do recall a couple weeks before this happened the A/C would not blow from the front vents, it cooled fine from floor of dash vents so I didn't thing much of it. It seemed to correct itself. I cant throw $14k into this vehicle so I am considering taking to a 3rd party shop (if I can find 1) or do what I can myself, historically I do all my own vehicle repairs but of course this is more of a computer with a bomb in it.

Before making this decision I'm curious if I should have Tesla replace the AC compressor to see if that allows the contactors to close. Any thoughts on this or better ideas?

Thanks again.

If the drive unit leakage is too high, replacing the compressor won't help. *
If the compressor leakage is too high, replacing the drive unit won't help. *
If the contactors are too damaged from opening under load, getting them to close won't get you to a working car.

*and if it does help, increasing leakage of the non-replaced component may eventually cause a repeat of the situation.

 

[shyboy]

Hi all, I need advice. I have a 2015 base model s, vehicle had no issues, codes or odd noises at the time of the most recent update. I did the update and on the next drive the vehicle failed. Tons of BMS error codes. Replaced 12v battery issues unchanged. Towed to service center and here is what I am being told:
1. Low isolation found in rear drive unit $7k
2. Pack contactors opened under load $5k
3. Low isolation in A/C compressor $1k

Here is my question as ignorant as it may be. Is there a chance that there is no issue beyond the contactors? It seems very odd that both the rear drive unit and the A/C compressor have issues out of nowhere. Does anyone have experience with these issues?

Thanks for any help!

How many miles on the car?
How is the battery health?
Whats the trade-in value?

Maybe time to trade-in and get a new one.

 

[dafish]

Cannot be very far out of warranty unless lots of miles. Tesla has no goodwill policy?

 

[Bryannearatl]

128,000 miles, battery and drive unit warranty expired 11/2022. Battery was charged daily to 75%. 100% = 217 miles. I am struggling with all 3 of these issues being legitimate. No signs of a single issue and immediately all 3 major issues at once...

 

[mongo]

128,000 miles, battery and drive unit warranty expired 11/2022. Battery was charged daily to 75%. 100% = 217 miles. I am struggling with all 3 of these issues being legitimate. No signs of a single issue and immediately all 3 major issues at once...

It's two related issues in 3 parts.

If the car detects leakage to the chassis from either HV rail, it will throw a fault and open the contactors. Normally, this check fails before the contactors are active and the car just doesn't power up all the way. However, if the leakage reaches the threshold while driving the contactors open while loaded which can damage the contacts.
The leakage measurement is taken on all HV devices. If the combined leakage of the drive unit and compressor exceed the limit, the fault is detected.
Say the limit is 1.0. The drive starts out with compressor leakage at 0.4 and drive unit at 0.5 . No fault detected even though there are two latent issues. However, during operation, the drive unit leakage increases to 0.6. Now, the total leakage is 1.0, and the car opens the contactors.
At the service center, they check the parts individually and see the higher leakage of the compressor and drive unit and, I'm guessing, do a resistance check on the contactors.

 

[Bryannearatl]

mongo, thanks for sticking with this. Do you have experience with service centers to know if they will release the details of the diagnosis? Your response makes sense but for more sense in the computing side of things not necessarily on a mechanical/ budgetary level. Meaning, using your hypothetical explanation, if compressor leakage is 0.7 and DU is 0.3 I would opt to replace compressor and hold off on replacing DU. This would allow me to save money for an upcoming DU repair or search for a replacement on my own.

I think this is one of the issues Tesla will face more and more as their vehicles age. If they want to avoid the idea that their product is disposable they need to be able to diagnose with more detail. There seems to be very little to no repair everything is here is the code so replace.

 

[mongo]

mongo, thanks for sticking with this. Do you have experience with service centers to know if they will release the details of the diagnosis? Your response makes sense but for more sense in the computing side of things not necessarily on a mechanical/ budgetary level. Meaning, using your hypothetical explanation, if compressor leakage is 0.7 and DU is 0.3 I would opt to replace compressor and hold off on replacing DU. This would allow me to save money for an upcoming DU repair or search for a replacement on my own.

I think this is one of the issues Tesla will face more and more as their vehicles age. If they want to avoid the idea that their product is disposable they need to be able to diagnose with more detail. There seems to be verlittle to no repair everything is here is the code so replace.

No first hand data. @wk057 does as a day job.
Services | 057 Technology
It could also be the drive unit is 1.2 and the compressor is 0.3 ...

 

[blodg1]

Hi all, I need advice. I have a 2015 base model s, vehicle had no issues, codes or odd noises at the time of the most recent update. I did the update and on the next drive the vehicle failed. Tons of BMS error codes. Replaced 12v battery issues unchanged. Towed to service center and here is what I am being told:
1. Low isolation found in rear drive unit $7k
2. Pack contactors opened under load $5k
3. Low isolation in A/C compressor $1k

Here is my question as ignorant as it may be. Is there a chance that there is no issue beyond the contactors? It seems very odd that both the rear drive unit and the A/C compressor have issues out of nowhere. Does anyone have experience with these issues?

Thanks for any help!

What firmware are you on now?

 

[Bryannearatl]

What firmware are you on now?

According to the app 2023.26.7

 

[brainhouston]

OP, unless u have External Isolation codes in history, I don't think AC or DU are ur immediate issues... Maybe they're on the way out soon...
Tesla been wrong before on many occasions.. n often does shotgun approach..
Fix contactors first then see if it drives ok
Replacing contactors isn't too hard, just nned to pull the battery. Obviously u might need codes erased, not sure about that one.

However, if the leakage reaches the threshold while driving the contactors open while loaded which can damage the contacts.

This is incorrect..
I drove with Isolation errors (went down to 20kOhm) and it didn't stop the car.
This is why u get 'car may not restart' error. Tesla gives u a chance to get to shop or somewhere safe instead of cutting ur car in the middle of the road.

If u have newer pack with pyro fuse on the bottom, see my HV pack repair thread here, might be useful:

Car died. BMS errors f123, w123, w073, w035, w142, w158

Unfortunately my 2016 MX 90D decided to surprise me with these errors :confused: We had a few days of cold/snow days and the car did fine. Last couple of days its been above freezing and everything already melted. I drove the car in the morning, then parked on driveway. Few hours later, started...

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