Built 8/2018 - Model 3 LR AWD - HV Battery issue or 12V issue?

[xdriv3]

Hoping this is the right forum to post--- looking for some thoughts on my situation.

I'm the original owner of a Model 3 LR AWD, currently at 45k miles. Picked up back in Sept 2018. Car has been flawless. Wife was driving home today when mid drive, she saw the error BMS_a035. Car continued to operate fine all the way back home.

By the time I got to it, more error codes on the screen-- BMS_a035, VCFRONT_a192, BMS_a151.

Went on Tesla app to schedule appointment. Technician reaches out for more details -- I didn't really have much more info at that time.

I was working outside my house and keep hearing loud thunking/clanking coming from the car -- perhaps it was from the HV contacts? So I went back into the car and entered the Service Menu. More codes popping up now---

BMS_a035, BMS_a151, VCRIGHT_a538, VCFRONT_a548, VCFRONT_a192, VCFRONT_a447. I took a few pictures of the HV and LV section (see attached).

At this point --- the car is no longer driveable (can't be shifted into gear), the windows for some odd reason automatically drops down and seems really low (low power?)

Car is safe, I left the frunk popped open (I expect the 12V to run dry at any time now). SOC shows about 170miles left.

Car is out of basic warranty, I still have the battery/drive train warranty.
I also pursued the extended warranty from X-Care.

What do you guys think it is? My 12V is certainly due for replacement (running since 9/2018). Could this still be a HV issue w/ the contacts?


Any insights appreciated!

 

[Lightbulb]

Im in a similar boat. 2021 Model 3 though, 95,300 kms on it and basic warranty was out at 80,000 kms and around 78,000kms I had the heat pump and super manifold changed out. did a cross Canada road trip last month, and when I got back I got the VCfront_a447 warning or the "cabin climate requires service", then after a reset it went away for 2 weeks, till today.

I booked an appointment which is tomorrow morning and today I tried to tackle the issue myself. I changed the cabin filters which were so frickin dirty, so I was hoping that was it. I went into service mode to perform a HVAC test again (failed before I changed the filter), and it worked.

then I went for a drive around to do some errands and kept climate on while in the store and came out to foggy windows and the "cabin climate needs service" warning on and going into service mode showed that there was 5 active alerts.

VCRIGHT_a538_hvacSystemNotNominal
VCFRONT_a447_cabinHVACUnavailable
VCFRONT_a161_compressorSelfFault
VCSEC_a117_VCLEFT_MIA
VCSEC_a116_VCRIGHT_MIA



VCFRONT= Vehicle Controller Front for the front fog lights, HVAC, sensors, etc
VCLEFT = The Vehicle Controller Left, for the steering column, left seats, left window, left mirror, locks, etc
VCRIGHT =Vehicle Controller Right , for the right seat, right windows, right mirror, etc
VCSEC = Vehicle controller Secondary on model 3/y, security, alarm, charge port, trunk, frunk, etc




When im in service mode, my 12v battery is reading between 13-14V which from my mechanical background, tells me that's where it should be. Yours is a little low, so honestly if I was you, I would start with the 12v battery. I thought that would be my issue, and maybe it is. having all these warnings almost tells me its something electrical like a harness has worn through or something

 

[EVRider-FL]

You’re overdue for a 12V battery replacement, which isn’t too expensive. I would start there and see if it resolves the other issues. You have nothing to lose since you will need to replace the 12V anyway.

 

[KenC]

Any electrical issue, the first thing I'd do is think about the 12v. It's so cheap and easy to replace, why wouldn't you do it to make sure? Plus, in the OP's errors, the 12v is definitely not charged enough.

Whether the low condition is caused by a PCS fault, impossible to say, but I would think a fresh 12v might allow you to drive to a service center.

My 3 also had a battery from Sept 2018, so I replaced it at around 48months, just to be on the safe side.

 

[xdriv3]

I agree with the point about replacing the 12V.

Would it make sense to have it towed to the tesla and have them do it and if it fixes problem, great. If not, more diagnostics to be done at that point.

I have AAA and I also have the X-care extended warranty plan.

Does it make sense to call AAA to do the battery swap first? Or just tow it to Tesla? I reached out to the service center and asked if they can send someone/mobile tech to do the 12V swap. But they’re declining as they need to do a Hv circuit integrity check for $230.

I have free towing through AAA and the extended service contract, if that matters.

Thoughts?

 

[boriszima]

I got my car around the same time as you and got about the same miles. I already changed my 12V battery last year, but i got a warning about 12v battery explicitly. You chatting with Tesla implies they can't diagnose an issue remotely? Errors kind of point towards your HV battery not 12V, but i haver zero electrical knowledge.

 

[KenC]

I agree with the point about replacing the 12V.

Would it make sense to have it towed to the tesla and have them do it and if it fixes problem, great. If not, more diagnostics to be done at that point.

I have AAA and I also have the X-care extended warranty plan.

Does it make sense to call AAA to do the battery swap first? Or just tow it to Tesla? I reached out to the service center and asked if they can send someone/mobile tech to do the 12V swap. But they’re declining as they need to do a Hv circuit integrity check for $230.

I have free towing through AAA and the extended service contract, if that matters.

Thoughts?

Obviously, it's your decision. Most would have it towed. Me, towing is just another opportunity to have the car damaged by someone who doesn't know Teslas, so I might do a 12v swap, if I had a backup handy.

After 3yrs, I bought a backup 51R for roadtripping, so I had one, but if you don't, then it's probably safest to get it towed to the service center.

 

[xdriv3]

I got my car around the same time as you and got about the same miles. I already changed my 12V battery last year, but i got a warning about 12v battery explicitly. You chatting with Tesla implies they can't diagnose an issue remotely? Errors kind of point towards your HV battery not 12V, but i haver zero electrical knowledge.

I never got the 12V replacement warning. That error didn’t pop up until the car completely died. I believe once I parked the car, it wasn’t able to “sleep”. I kept hearing the battery connector making the clanking noise from outside every few minutes. it stopped once, based on my assumption, the 12v was completely depleted.

 

[Lightbulb]

Im in a similar boat. 2021 Model 3 though, 95,300 kms on it and basic warranty was out at 80,000 kms and around 78,000kms I had the heat pump and super manifold changed out. did a cross Canada road trip last month, and when I got back I got the VCfront_a447 warning or the "cabin climate requires service", then after a reset it went away for 2 weeks, till today.

I booked an appointment which is tomorrow morning and today I tried to tackle the issue myself. I changed the cabin filters which were so frickin dirty, so I was hoping that was it. I went into service mode to perform a HVAC test again (failed before I changed the filter), and it worked.

then I went for a drive around to do some errands and kept climate on while in the store and came out to foggy windows and the "cabin climate needs service" warning on and going into service mode showed that there was 5 active alerts.

VCRIGHT_a538_hvacSystemNotNominal
VCFRONT_a447_cabinHVACUnavailable
VCFRONT_a161_compressorSelfFault
VCSEC_a117_VCLEFT_MIA
VCSEC_a116_VCRIGHT_MIA



VCFRONT= Vehicle Controller Front for the front fog lights, HVAC, sensors, etc
VCLEFT = The Vehicle Controller Left, for the steering column, left seats, left window, left mirror, locks, etc
VCRIGHT =Vehicle Controller Right , for the right seat, right windows, right mirror, etc
VCSEC = Vehicle controller Secondary on model 3/y, security, alarm, charge port, trunk, frunk, etc




When im in service mode, my 12v battery is reading between 13-14V which from my mechanical background, tells me that's where it should be. Yours is a little low, so honestly if I was you, I would start with the 12v battery. I thought that would be my issue, and maybe it is. having all these warnings almost tells me its something electrical like a harness has worn through or something

Not to jack the thread, just want to complete the story for any future readers who have my issue

Tesla appointment today went well as they replaced my heat pump again. I was 15k Kms passed warranty period but I suspect because they changed my heat pump a couple thousand before my warranty expired, they did this a goodwill or otherwise I’m not sure why it was completely covered, I never got a straight answer as I was just super happy to have it fixed

The Tesla service around me is super reasonable. I would ask what a new 12b battery instal would be. Might only be like $100 bucks and therefor worth it to have in the vehicles history that Tesla is the ones that changed it

 

[KenC]

I never got the 12V replacement warning. That error didn’t pop up until the car completely died. I believe once I parked the car, it wasn’t able to “sleep”. I kept hearing the battery connector making the clanking noise from outside every few minutes. it stopped once, based on my assumption, the 12v was completely depleted.

Well, it does sound like a PCS error, which resulted in a drained 12v.

 

[jjrandorin]

I agree with the point about replacing the 12V.

Would it make sense to have it towed to the tesla and have them do it and if it fixes problem, great. If not, more diagnostics to be done at that point.

I have AAA and I also have the X-care extended warranty plan.

Does it make sense to call AAA to do the battery swap first? Or just tow it to Tesla? I reached out to the service center and asked if they can send someone/mobile tech to do the 12V swap. But they’re declining as they need to do a Hv circuit integrity check for $230.

I have free towing through AAA and the extended service contract, if that matters.

Thoughts?

I have AAA, and have had them replace batteries in cars before. With that being said, when I had a dead battery in my BMW, they did not have, or even know how to, replace the battery in that vehicle (BMW uses AGM batteries).

I suspect that if you are expecting the AAA towtruck to have the specific battery that tesla uses, you will be sorely disappointed. If you want to call AAA to tow you car, thats a separate thing and if you dont want to replace the battery yourself, I can see that.

I wouldnt call AAA and expect them to replace your 12V battery though, as they send a little pickup truck (not a tow truck) on battery jobs for jumps / battery replacements (at least in this area), and you run the very real risk that they would show up, tell you "we dont have that battery / change batteries in teslas", then suggest you call in for a towtruck with the additional wait.

You could also just schedule mobile service to replace your 12v, but if I had all those errors I would probably call AAA to have it towed to a local SC, if it were me.

 

[Lightbulb]

Not to jack the thread, just want to complete the story for any future readers who have my issue

Tesla appointment today went well as they replaced my heat pump again. I was 15k Kms passed warranty period but I suspect because they changed my heat pump a couple thousand before my warranty expired, they did this a goodwill or otherwise I’m not sure why it was completely covered, I never got a straight answer as I was just super happy to have it fixed

The Tesla service around me is super reasonable. I would ask what a new 12b battery instal would be. Might only be like $100 bucks and therefor worth it to have in the vehicles history that Tesla is the ones that changed it

And less than 24 hours later my car is blowing hot air and cannot cool. No warning on the dash but I know something is wrong

Again updating for those who in the future might run into this issue

 

[xdriv3]

Car diagnostic done. I was told the PTC heater needs to be replaced. There was nothing wrong w/ the 12V.

I'll replace the 12V anyway since it's been 5 years.

Thank god for my extended service contract. Looks like I'm covered for the heater replacement.

 

[zgeorge]

Hoping this is the right forum to post--- looking for some thoughts on my situation.

I'm the original owner of a Model 3 LR AWD, currently at 45k miles. Picked up back in Sept 2018. Car has been flawless. Wife was driving home today when mid drive, she saw the error BMS_a035. Car continued to operate fine all the way back home.

By the time I got to it, more error codes on the screen-- BMS_a035, VCFRONT_a192, BMS_a151.

Went on Tesla app to schedule appointment. Technician reaches out for more details -- I didn't really have much more info at that time.

I was working outside my house and keep hearing loud thunking/clanking coming from the car -- perhaps it was from the HV contacts? So I went back into the car and entered the Service Menu. More codes popping up now---

BMS_a035, BMS_a151, VCRIGHT_a538, VCFRONT_a548, VCFRONT_a192, VCFRONT_a447. I took a few pictures of the HV and LV section (see attached).

At this point --- the car is no longer driveable (can't be shifted into gear), the windows for some odd reason automatically drops down and seems really low (low power?)

Car is safe, I left the frunk popped open (I expect the 12V to run dry at any time now). SOC shows about 170miles left.

Car is out of basic warranty, I still have the battery/drive train warranty.
I also pursued the extended warranty from X-Care.

What do you guys think it is? My 12V is certainly due for replacement (running since 9/2018). Could this still be a HV issue w/ the contacts?


Any insights appreciated!

Gosh! 2018 LR RWD here (Original owner). Same experience: car has been flawless.. ...until yesterday, pulled into the driveway after as I always do and BAM! BMS_a035. I dropped it off at the earliest SC appointment I could get. SC says they needed to run diagnostics and need to keep the car. It's been 48hrs, heard nothing. What did your issue end up being?

 

[Tuba2020]

I joined the BMS_a035 club before yesterday. 2018 M3 Long Range RWD. My mileage is 37K so still have battery and drive warranty... Had 60miles left in my battery. Weather temperature was around 50 F. Driving into the parking building at my work suddenly I saw the error msg and that the car might not start. I parked and it restarted. But when I came back 2 hours later the car was dead.. Restarted.. but it slowly rolled down the driver side window until it stopped.. Tesla was not ready to do a remote diagnostics they asked me to take for service they said they can not tell if covered under warranty untill they do diagnostics.. Now.. go find a someone to tow from a low clearance central parking.... 3 hours calls and $260 to take the car to the Tesla center 6 miles way... Tesla wanted to give me $100 uber credit which is useless (pick up my child with uber from daycare) then they offered a loaner.. First they quoted me $210 diagnostic fee. 2 days later they updated the diagnostic fee to $315... So as of now I am out of $575 before any repairs.. Will update the thread as it progresses but for now.. I feel that It was a mistake to replace my principle to only buy Toyota or Honda.. My Toyota Matrix I used for 15 years and never broke down and only had to do mindor repairs for around $500 in 15 years..

 

[xdriv3]

Sorry for the late reply!

It was a PTC heater issue. It was replaced and was $870. CareX warranty covered it less the deductible

Gosh! 2018 LR RWD here (Original owner). Same experience: car has been flawless.. ...until yesterday, pulled into the driveway after as I always do and BAM! BMS_a035. I dropped it off at the earliest SC appointment I could get. SC says they needed to run diagnostics and need to keep the car. It's been 48hrs, heard nothing. What did your issue end up being?

Gosh! 2018 LR RWD here (Original owner). Same experience: car has been flawless.. ...until yesterday, pulled into the driveway after as I always do and BAM! BMS_a035. I dropped it off at the earliest SC appointment I could get. SC says they needed to run diagnostics and need to keep the car. It's been 48hrs, heard nothing. What did your issue end up b

 

[Tuba2020]

Gosh! 2018 LR RWD here (Original owner). Same experience: car has been flawless.. ...until yesterday, pulled into the driveway after as I always do and BAM! BMS_a035. I dropped it off at the earliest SC appointment I could get. SC says they needed to run diagnostics and need to keep the car. It's been 48hrs, heard nothing. What did your issue end up being?

So strange that this is happening almost at the same time I also picked up my Model 3 on Sept 2018.
@zgeorge: did your diagnostic come back? Mine took 2 weeks and I am told:

"Part Quantity Unit Price Price Adjustment Subtotal
HVAC, PTC SERVICE
ASSY(1107677-00-A)
13.00
PTC HEATER DUAL
ZONE(1088218-00-I)
550.00
HIGH VOLTAGE
ANCILLARY
HARNESS(1109004-00-
D 75.55

Labor around 240

Diagnostic 210
...
"

What is the PTC heater doing? Is this the cabin heater? and if so why should a car completely stop working if the cabin heater stops?

Ok. I am find with the repairs just want to makes sure the car not stops on my next trip as other forums were saying their drive unit inverter had to be replaced...