Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

High Voltage Interlock Loop (HVIL) Issue - Questions

I'm dealing with the same problem now. 3rd time in 3 months. First Tesla diagnosed it as a drive unit problem, second time (about 8 weeks later) a bad connector pin, and this time who knows. I can't drive it yet. Intermittent, though, so hopefully I will be able to start it soon.

This can't be a 12v battery issue, can it?

I felt uncomfortable with their initial diagnosis of a drive unit fault. Drive unit is AC. Other side of the inverter. How could that trigger HVIL issues? I don't feel good about Tesla's ability to diagnose and fix these issues. My car is a 2014, so it's 8 years old (almost).
 

MP3Mike

Well-Known Member
Feb 1, 2016
20,445
51,936
Oregon
I felt uncomfortable with their initial diagnosis of a drive unit fault. Drive unit is AC. Other side of the inverter. How could that trigger HVIL issues? I don't feel good about Tesla's ability to diagnose and fix these issues. My car is a 2014, so it's 8 years old (almost).
The drive unit contains both the motor and inverter. The power going to the drive unit is high voltage DC.
 
Exactly a year ago I reported here that I had this "unable to drive" issue and it turned out to be the battery heater.

Now it did it again.. :( Probably a different issue this time.

We were at my father-in-laws place, 300km from home (and 400km from nearest SC). Father-in-law is an EV skeptic, always questioning how we can manage with EV during winter etc. He took photos while a tow truck was pulling the car away.. :) Sigh. Luckily my insurance covers the towing and train tickets +taxi for whole family, so car is now safely in SC and we are at home.

On the bright side, I was 100% sure that my 8 year battery warranty has expired on 10/2021, since the car has been first registered in 10/2013. But now I stumbled on the warranty page in Tesla app and it says I have warranty until 6/2022! I took a screenshot that in case service center disagrees. :)
Perhaps the car was sitting in Tesla stock 10/2013 - 6/2014, already registered? Also the regular 4 year warranty has expired in 6/2018.

Anyway, I'm now looking for a newer MX to replace this MS before the warranty runs out.. Newer MS is really not an option because we are a family of 6 and the rear "jump seats" are not available for newer cars. Also tiny frunk in newer MS. This 2013 P85+ was pretty much perfect in that aspect, could easily fit 6 people and luggage, and even baby stroller in the frunk.

Useless post, sorry. :) Just venting my thoughts!
 
  • Like
Reactions: FrozenCanuck
Ok I got my car back. They didn't actually fix it! They said the car was working when they got it from the towing company, and couldn't reproduce the fault.

However the diagnostics is quite interesting:

1647951491680.png


They offered to replace the HVJB but I refused because it was a 2000eur part...

Anyone know what microswitch they are talking about and is DIY replacement possible?

Edit: Total cost for this service was 280eur + tax, which I think is fairly OK when considering the amount of diagnostics.
 
@danielk04 I think the microswitch can be seen even in your picture, I adjusted the brightness and zoomed it.

I also found some more pictures online:

It would be great if I could find correct type before disassembling anything, so it could be replaced right away. Anyone have spare HVJB lying around so could check the type?

It does look more like a proximity switch, not a microswitch.

Car is driving fine at the moment, though. But I'm selling the car soon, and hate to leave such ticking timebomb there knowing that it's a 2000€ fix if Tesla does it, and I have the tools and skills to fix it myself for 5€ probably..
 

Attachments

  • InkedHVIL 1_LI (3).jpg
    InkedHVIL 1_LI (3).jpg
    95.1 KB · Views: 156
Bah. Turns out I have HVJB gen2, which is entirely different from above photos and does NOT have the proximity switch.

Perhaps it's already replaced earlier, surely a 2013 car should have gen1? Or perhaps gen1 was US only? Europe obviously has different parts because chargers are 3-phase..

Isn't there another "HVJB" in front, behind the frunk? Maybe SC meant that one, it doesn't specify front or back in the description..
 

Attachments

  • 20220326_102726.jpg
    20220326_102726.jpg
    833 KB · Views: 108
  • 20220326_101959.jpg
    20220326_101959.jpg
    530.8 KB · Views: 104
Bah. Turns out I have HVJB gen2, which is entirely different from above photos and does NOT have the proximity switch.

Perhaps it's already replaced earlier, surely a 2013 car should have gen1? Or perhaps gen1 was US only? Europe obviously has different parts because chargers are 3-phase..

Isn't there another "HVJB" in front, behind the frunk? Maybe SC meant that one, it doesn't specify front or back in the description..

If you have a gen2 DC/DC you also have a seperate front HVJB in the frunk.

With gen1 the HVJB is a combined housing with the DC/DC inside the front passenger wheel well
 
If you have a gen2 DC/DC you also have a seperate front HVJB in the frunk.

With gen1 the HVJB is a combined housing with the DC/DC inside the front passenger wheel well

Yeah, I already got confirmation from the SC that my car only has HVJB in the rear, and that was the one they suspected has a failing microswitch.

.. except that I opened it and there is no microswitch, so I assume the diagnosis was wrong. :)

I think the only choice now really is to wait if it happens again and hope the failure lasts long enough to be able to measure where exactly HVIL is cut..
 
Yeah, I already got confirmation from the SC that my car only has HVJB in the rear, and that was the one they suspected has a failing microswitch.

.. except that I opened it and there is no microswitch, so I assume the diagnosis was wrong. :)

I think the only choice now really is to wait if it happens again and hope the failure lasts long enough to be able to measure where exactly HVIL is cut..
Hmm, I checked the wiring diagram and every Model S after 31 may 2013 has a switch inside the HVJB due to safety precautions. Manual is talking about a reed switch and not a microswitch or something so maybe it's behind the orange plastic?

So you don't get any errors when the lid is removed?
 
I didn't try power on with the lid open..

But in the earlier photos with gen1 HVJB the switch is very easily visible. Nothing like that in gen2..

However I can't inspect this further, I traded the car for a 2016 MX P90DL. :) I did honestly tell the dealer that my car was just in service for HVIL error and that no parts were changed because the car started working by itself.
 
This all just happened to me in my 2022 X Plaid with 183 miles! The tow truck driver said "Is this brand new? Did you just do a software update?" I said yes and yes. he said "we're seeing a lot of these." Service said it was a "battery disconnect" and that they are replacing the 12V battery.
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top