Error codes on 2014 P85 MS, Please help
I bought a used Tesla Model S P85 2014 with 135k miles in July. It has been so much fun! Last night, I drove 20 miles to my house, and as I was pulling into my house, it came up with a warning.. I can't remember exactly what it said, but something about "may not restart".
I pull into my garage, plug it in and go to sleep. I woke up this morning to use it, and the screen tried to turn on but then shut off...
I googled and figured out how to do a "soft reset" (hold steering wheels plus brake for up to 2 minutes), nothing. Something about a 4 finger wheel reset (2 on wheels, 2 buttons above and hold brake). Nothing.
I tried doing a hard reset... Which is disconnecting the 12v battery, waiting 2+ minutes, then reconnecting it.
I got the screens to turn on, and enough to grab error codes, but after about 60 seconds... It goes back to shutting off.
Error codes:BMS_f008 - Vehicle may not restartBMS_w008 - Vehicle may not restartBMS_w009 - Service is requiredGTW_w017 - Electrical system power reducedGTW_w018 - Electrical system power reducedGTW_w157 - Power reduced (vehicle systems shutting down)DI_u014 - Unable to drive (voltage supply too low)
I set an appointment up with Tesla, but the soonest I can get in is Tuesday morning. I checked the voltage on my 12v, and got 11.92... when I take off the negative terminal, I get 4.0 volts. I'm suspicious it's my 12v battery
PLEASE NOTE IM NOT VERY SMART AT THIS. In no way am I professional. I was simply curious whether I could buy a new 12v battery to stick in so I have a car for the weekend.
Sounds like they will charge $88 to do a diagnosis. I will have to tow it to them as well (17 miles).
Anyway, just curious if anyone has seen these errors before, and what I could try while I wait for Tuesday.
I appreciate any comments or advice! Thank you 📷
It seems the smartest thing to do is to wait until Tuesday, pay the $88 for them to diagnose it, and hopefully it is something under warranty?
Edit: my appointment is Tuesday 10/5 at 9AM. I will update then :)
Edit 2: I replaced the 12 volt battery myself, and everything appears back to normal. Drove around for 30 minutes just fine. I'll still be going to Tesla service center tomorrow.
Tesla can send mobile service to replace your 12v battery if that's the issue.
However, your codes seem more consistent with your HV battery pack failing; when the 12 volt fails, the error messages are different and the failure is usually not that dramatic. One bad cell in one module (around 450 cells per module, 16 modules in a full pack) is enough to disable your vehicle.
If there's any life left, drive it over to the service center and leave it there until they can look at it. It will most likely be covered under warranty but you may be out of a car for a couple of weeks. You might be able to get a loaner from Tesla or at least a crap ton of Uber credits.
I'm honestly surprised Tesla hasn't remotely diagnosed your car based on those error codes.
Your 12V battery needs to be replaced
Would you suggest I could go to Auto zone, get a new 12v battery, to install myself? Do stores like Auto zone sell 12v batteries for Tesla?
I assume 12v battery is not under warranty?
No you shouldn’t go to Autozone. They don’t have the same 12V battery. If you can just drive by the service center they will help you right away. Just ask nicely.
Edit: I don’t think 12V battery will be covered under warranty
Thank you! Looks like the service center is closed until Monday. I'll just have to be patient till then.
Your car will be unable to drive by then. Sometimes they still operate on Saturday just not taking clients. Just try your luck or else by Monday you would need to tow it 😐
u/teltic - This is correct. The 12v is on limited time. I would drive it there immediately and Uber back home.
Maybe you’ll get lucky, but it’s better than towing it.
Based on the above description I doubt it drives right now anyway.
Things that shouldn’t be in a Tesla because there’s a way better way to do it. Elon, seriously get rid of that damn battery. GaN PWM bucks can step down on demand at the amperage you need at 99% efficiency. There’s no reason to have a lead acid battery that’s in a constant state of discharge.
The 12V battery lets the electrical system stay powered while totally disconnecting the main battery. Even the new S has a 12V battery, it's just lithium now.There's a lot of good reasons you want to disconnect the main contactors, it reduces drain, improves safety, allows better balancing and health monitoring.
There are other ways of doing that same thing and isolating the 12v draw that still eliminates the secondary battery. Lion is slightly better but still has issues and is increasing complexity. Most of what is one the 12v battery doesn’t even need to be on all the time so shut it off with the main battery and put a small LTO in for the very few things that do and almost all of those will be 5v or 3.3v not 12v (Ie all computers step down to 3.3v for virtually everything now a days) and thus you could use a single 65xxx lto with 30 year life and 3c discharge for those few things and only while the main battery is off for standby functions and then use a mosfet to switch to main when it’s on.
https://www.ohmmu.com/product-page/12v-lithium-battery-for-tesla-model-y
I bought this for my Model Y.
Tesla is moving to a separate Li-ion battery. For safety reasons it needs to be separate. The Li-ion battery is a lot lighter.
12v replacement on this generation car is quite involved. It's located deep in the passenger fender well and covered by unfriendly electrical components. The Tesla fee for replacement includes installation and it's well worth the $30ish in labor to let them do it. I'm all for DIY, But risk/reward makes this a no brainer t me vs potential savings.
Why do they still use a 12v lead acid battery?
Because 12 volt is the standard for cars and car components, and lead acid was the best choice when they designed the S. If they used the main battery, the entire car would be dead if you ran it out of juice or had a failure. This way, even when stranded by the side of road you still have some basic car controls and emergency lighting running from the 12v.
They do make 12v lithium batteries.... That's why I specifically added lead acid.
They make 12v lithium batteries now. I’m sure the selection was very different in 2005 when they started designing the Model S.
And that's why I said "still"...
Stick a charger on your 12v, it won't hurt anything.
Based on your description it sounds like your 12v is failing. Pretty common actually. They make 3rd party 12v batteries for Tesla's now that are Lithium based. They are more expensive, but last much longer than the lead acid versions, so it works out the same. Since you are out of warranty I'd replace the 12v myself first. Look into the Lithium version, but if you find it too much, you can always buy the older lead acid style.
Just adding, the lead acid battery used in Tesla’s are AGM type batteries that require special chargers. A lot of chargers these days support AGM, but you need to check.
Lots of replies saying 12v but unfortunately this advice is incorrect, the 12v discharging is just a symptom, there is something underlying preventing the HV system from charging the 12v. The car will almost never just stop charging the 12v regardless of how degraded the 12v battery becomes.
You want to book an appointment ASAP to have it properly diagnosed.
Update: I replaced the battery by myself... And it worked for another 30 days. Then it gave me the same error codes. Tesla fixed it under warranty... Saying it was some chip in a module that failed. This took them 3 weeks to get the part and fix....
Well.... A month later. My car just stopped charging and gave me these errors
GTW_w018 BMS_f008 BMS_w008 BMS_w157 DI_u014
This has been a painful 6 months of ownership so far. My warranty last until May, and I'm not sure if I should drive this outside of warranty...
I will update when I find out what needs to be fixed
Based on the error codes I'm going to guess your high voltage battery is toast. And since it's bad it can't charge the 12V. If it's a 2014 it should still be covered by the battery and power train warranty.
The HV battery is rather difficult to destroy. The most likely problem is the lead acid battery itself, if that’s okay, the next component to diagnose would by the DC-DC converter. That’s the component that steps down voltage from the HV relay to the 12V accessory system (at 14 volts)
Unless it's a very VERY early 2014 build, the fuse should be replaceable. Prior to that the whole unit was replaced, about $2000. I think the change was late Jan/early Feb. People with earlier units have replaced the fuse themselves, but it's not something Tesla will do and owners aren't equipped to determine why the fuse failed in the first place, so underlying faults might go undiagnosed.
I’d immediately think the 12v based on the Electrical System Power Reduced and the fact that the screen isn’t turning on. The question is is it just the 12V or is it the DC-DC converter not charging the 12V…
The voltage supply too low one though… I’m not an expert, but that sounds to be HV pack related. It could be a fluke due to 12V power being low though. They can cause screwy messages.
DI_u014 almost always means that the HV relay is open. If the voltage of the HV was too low, the trouble side would being with BMS.
Could you explain a bit more? Do you think it is the main battery or 12v battery?
Your need a new 12v battery. Honestly, the fact that it made it this long is a miracle. The Model S 12v battery was seeing an average life of two years.
Leave it alone and let Tesla fix it and why would you ever buy a car with 135k miles
I replaced mine and I am very good with cars, but that battery is a pain in the ass to replace because of where it sits under windshield. About 200 on ebay.
I've already gotten to where the battery is. I just need to disconnect the DC 2 DC Cable and... A positive terminal off to replace?
But at the same time it's probably smarter to just get it replaced professionally
Yes. It would be wise, it can get a little tricky.
When this happens, request roadside service on your phone app. Tesla will advise you soon after.
Like others said, its your 12v. It is covered under warranty, Happened to make last year on an 2014 S85 and Tesla paid to have it towed and replaced the battery the same day. I never got a DTC about it, jsut came out one day and there was no power. If you get the DTC, act quickly!
Thanks for your response! What is DTC?
Diagnostic trouble code. The codes / messages that came up.
Perfect thanks for your help :)
Either 12v or you have a fault in you hv battery most you will be out is 200 bucks.
Sounds like a dead 12volt battery
I had a similar set of error codes when I bought my 2021 Tesla Model 3. It turned out the high voltage battery “wasn’t plugged in all the way”. The service center also replaced the 12v battery under warranty. Took four days in the shop.
I had a a similar error from my 2014 MS 85 It turned out that the 12v battery only was the symptom as already suggested. The culprit was a fuse box on HV battery that had taken in water. Consequently it was unable to charge the 12v battery (and pretty much any thing else for that matter). Fixed by the local SC on warranty.
This is probably not a faulty 12v. it sounds like you have a problem inside the high voltage junction box. Here's a thread that sounds similar to your problem. Unfortunately, not likely covered under warranty but the replacement cost isn't too bad: https://teslamotorsclub.com/tmc/threads/failure-of-the-high-voltage-junction-box-2014-model-s.227575/
the 3 GW codes are saying your 12v is low. however, this does not always mean 12v is faulty.
BMS_f008. is saying your high voltage interlock loop is open.
BMS_w008 will set if you were previously in drive but when you park the contactors stayed closed (energized) when the car requested them to open. When this code sets, the car will be unable to support 12v using the dc-dc converter. This means your 12v will eventually become low and die. So, low 12v is a symptom in your case, rather than the problem.
You're very fortunate. You're still under warranty and will get a refurbished main pack for free. I had this happen and they quoted me 14370+tax because my 2013 P85 was 3 months out of warranty. I fortunately was able to fix it myself for about $50 in coolant and some sealant.
Looks like a high voltage isolation fault. Either the heater, air conditioner, drive unit, or battery is likely failed.