2014 85 HV Battery BMS_u029 error 1 month out of warranty and after a recent OTA update, Who else?

[Recell]

in the case of the 85/90 kWh packs, each has 16 modules in series with 6 ‘bricks’ in each for a total of 96 bricks in series

each brick contains 74 cells in parallel.

so 16x6x74=7,104 cells total.

the nomenclature for this kind of pack is 96s74p - 96 in series, 74 in parallel

and in the case of 70/75 kWh packs it’s 14 modules with 6 bricks in each and 74 in parallel

so 84s74p with 6,216 cells total

 

[vcor]

I'll also add that the term "Bricked" means the battery pack is dead and unrecoverable. This can happen if you leave a car uncharged for > 6 months or so. The cells become so discharged, they are damaged and must be replaced. I'm not sure I've heard of a Tesla in the last 7 years becoming bricked, but I'm sure it has happened. It was more common with the Roadster, as someone would leave it uncharged for a while, and it didn't have the systems to try and prevent bricking as was started with the Model S.

 

[SSedan]

2014 Tesla S P85 125K miles
Being told it has a dead cell and needs pack replaced.
warranty expired 11/29/22 failure 1/20/23 I believe there was a OTA update in decemeber.

 

[Jeff92se]

Question. It seems that alot of the recent BMS_u029 codes coming after an OTA has happened after one more recent update?

If that is true, then would the chances of buying an used Model S with a working original battery a better bet now? Especially one with let's say 50,000 miles or so

 

[NV Ray]

Question. It seems that alot of the recent BMS_u029 codes coming after an OTA has happened after one more recent update?

If that is true, then would the chances of buying an used Model S with a working original battery a better bet now? Especially one with let's say 50,000 miles or so

Please see following response from Recell on the BMS-u029 and OTA update theory. Not sure the two are correlated, just bad timing. 2014 85 HV Battery BMS_u029 error 1 month out of warranty and after a recent OTA update, Who else?

 

[kakamora1919]

Same thing happened to me. Warranty expired 11-Feb-2023. BMS error received 20-Mar-2023. Tesla Model S 85.

 

[NV Ray]

Same thing happened to me. Warranty expired 11-Feb-2023. BMS error received 20-Mar-2023. Tesla Model S 85.

Join us on this FB Group I started. We're up to 92 members. Tesla BMS_u029 | Facebook

 

[maximizese]

I've had a "12V battery needs replacement warning" for 1yr/18K miles and now I'm wondering if I replace the battery and do a OTA, will I get the code for the HV battery as well. I had 256 miles of range at 100% before the 6/19 software update, then got 242-244 overnight from the software update, 2 years later it dropped suddenly to 232-236 range miles. I didn't see a steady decline, but tiered drops after software updates. Anyway, I might have to join Facebook one the day I get the dreaded code.

 

[NV Ray]

I've had a "12V battery needs replacement warning" for 1yr/18K miles and now I'm wondering if I replace the battery and do a OTA, will I get the code for the HV battery as well. I had 256 miles of range at 100% before the 6/19 software update, then got 242-244 overnight from the software update, 2 years later it dropped suddenly to 232-236 range miles. I didn't see a steady decline, but tiered drops after software updates. Anyway, I might have to join Facebook one the day I get the dreaded code.

Other than 2012-2014s (so far), for the folks that have gotten the BMS_u029 error code there has been no common thread. Not miles, range disparities, etc. Only 2012-2014s.

 

[maximizese]

Other than 2012-2014s (so far), for the folks that have gotten the BMS_u029 error code there has been no common thread. Not miles, range disparities, etc. Only 2012-2014s.

My suspicion is the BMS_u029 error code common thread might be the software update, insofar as the newer software update might searching for BMS errors in a parameter that the older software did not. It's similar to how some Model S owners with the 85 and 90kWh packs were resistant to software updates post April 2019, others refused to install v9 and v10 OS to avoid the Supercharging nerfing and range reduction. It's just my suspicion and I have no data to show this other than it appears that BMS error codes seem to be popping up a lot more and I'm not sure how many folks having updated their software in over a year.

 

[dmurphy]

My suspicion is the BMS_u029 error code common thread might be the software update, insofar as the newer software update might searching for BMS errors in a parameter that the older software did not. It's similar to how some Model S owners with the 85 and 90kWh packs were resistant to software updates post April 2019, others refused to install v9 and v10 OS to avoid the Supercharging nerfing and range reduction. It's just my suspicion and I have no data to show this other than it appears that BMS error codes seem to be popping up a lot more and I'm not sure how many folks having updated their software in over a year.

You should probably go back and read this thread from the beginning. @wk057 and @Recell explained quite well what’s happening here. It’s not the firmware.

 

[maximizese]

You should probably go back and read this thread from the beginning. @wk057 and @Recell explained quite well what’s happening here. It’s not the firmware.

Thanks. Sometimes I get lost in all the issues that pop up and it's hard to sort out what causes the issue and what seems to just coincide. Grateful for those with more knowledge because we're not exactly told what's going from Tesla nor their Service Center advisors. Right now I'm getting an activeaero and right shutter error in Service Mode that might be more of an error in my current software version (circa 2/22). My louvers appear to physically open and close just fine and can still hit up to 128kW at a Supercharger stall (for a few seconds that is). Was never clear if subsequent software updates patched the error I'm having or not. I'll have to get a new 12V battery and update the software to test that one out.

 

[dmurphy]

Thanks. Sometimes I get lost in all the issues that pop up and it's hard to sort out what causes the issue and what seems to just coincide. Grateful for those with more knowledge because we're not exactly told what's going from Tesla nor their Service Center advisors. Right now I'm getting an activeaero and right shutter error in Service Mode that might be more of an error in my current software version (circa 2/22). My louvers appear to physically open and close just fine and can still hit up to 128kW at a Supercharger stall (for a few seconds that is). Was never clear if subsequent software updates patched the error I'm having or not. I'll have to get a new 12V battery and update the software to test that one out.

The tricky thing here is that it can appear that the firmware causes it …. What happens is a full BMS reset is part of the firmware update process. That reset can make the BMS “notice” an issue, if you will, that’s gone undetected since the last BMS restart. So all of a sudden, the BMS restarts, says “hey, you got a problem” and bam. So it’s natural to think the firmware is the root cause, when the problem has actually existed for a while …. It’s just that the firmware caused the BMS reset, so we blame firmware.

Same with changing the 12v battery. Doing a full power down of the car will also do a BMS reset. I’ll leave it to the Smart Guys to indicate if whether the LV battery can be swapped “hot” (ie while the traction battery is supplying 12V) and what the side effects are …

But yeah. This is a tricky one!

As for the louver error — that’s way over my pay grade.

 

[vcor]

... Right now I'm getting an activeaero and right shutter error in Service Mode that might be more of an error in my current software version (circa 2/22). ...

Sounds like the known errant diagnostic message on older cars. See: Model S 2014 - active alerts just in service mode

 

[NewbyMaybe]

I've had a "12V battery needs replacement warning" for 1yr/18K miles and now I'm wondering if I replace the battery and do a OTA, will I get the code for the HV battery as well. I had 256 miles of range at 100% before the 6/19 software update, then got 242-244 overnight from the software update, 2 years later it dropped suddenly to 232-236 range miles. I didn't see a steady decline, but tiered drops after software updates. Anyway, I might have to join Facebook one the day I get the dreaded code.

You can replace the battery without an update.

 

[pepsundar]

While I want to believe that an OTA has nothing to do with battery pack failure, it's too hard for me to believe it, because last year in April, I came back from work in the evening after my usual 30 mile round trip commute, parked the car. Next day morning when I went back in to head to work, the screen displayed multiple warnings and yes there was an OTA that was installed the previous night. The car electronics were turned on, but I was not able to drive. It was one month after warranty expired. The car had to be towed to SC and SC said my RDU needs to be replaced. I understand some cells or a brick on a 7000+ cells could go wrong over time. But how come an RDU magically fails with no warnings whatsoever? And it failed after an OTA update. Is the RDU that fragile? My car had just 62k miles. No matter how much I tried, I couldn't digest that $8k bill. Tesla gave no reason as to why RDU magically failed with no warnings and right after the OTA update.

 

[Droschke]

While I want to believe that an OTA has nothing to do with battery pack failure, it's too hard for me to believe it

A new OTA can expose an issue which already has existed with your battery.

 

[pepsundar]

A new OTA can expose an issue which already has existed with your battery.

I understand that about battery. My question was on the RDU which failed magically after an OTA update and I had no prior warnings or performance degradation. My car had 63k miles then, two months past warranty. Are RDUs that fragile and can fail just like that?

 

[Droschke]

I understand that about battery. My question was on the RDU which failed magically after an OTA update and I had no prior warnings or performance degradation. My car had 63k miles then, two months past warranty. Are RDUs that fragile and can fail just like that?

The Large RDU's have issues discussed in multiple threads. Search for the posts contributed by @ajbessinger on this topic.

FYI, my Large RDU was replaced at 37k miles.

 

[NewbyMaybe]

Software is detecting issues earlier to prevent fires/bricking in traffic/bad press.