[Salvage vehicle] Tesla Model 3 2021 BMS: Vehicle configuration mismatch

[Nam Nguyen]

Hello,

I bought salvaged tesla model 3 2021 last month but the battery is from different car. As the battery for the car I bought already sold. I manage to disassemble from the put it back in the garage for some fun and education to my boys 12 and 8.

The battery is not able to charge. As I understand I need to make the vehicle to update the latest firmware from all different components by pressing firmware update. It doesn't allow me to update because the battery 0%. The battery is good 360VDC I measured. However, the contactor never click in that cause battery 0%. I measure the contactor control voltage from right body controller 0VDC so the control board not allow to close the contactor. (Maybe due to vehicle configuration mismatch).

Do you have any idea how to get the vehicle firmware update?
Can I need to use Tesla toolbox 3 to deploy the firmware?
Does it work by supplying 12VDC to close the contactor (bypass BMS) to get the battery status above 0% so I can upgrade the firmware online?

Many thanks in advance for you advice. We are now a bit stuck.

Best regards,

Me and my boys.

 

[Jeff_fixin]

Props on buying a salvage Tesla and not being afaid to tear into it. I bought a 2021 salvaged model 3 recently as well and am having fun trying to get it to charge. I have a different issue but my battery is also at 0mi which I am curious to see if this will cause any issues when I do fix the charging issue.

Bump for your answer, hope you are able to figure it out!

 

[smatthew]

DO NOT apply 12V to the contactor! The BMS has to pre-charge the HV system otherwise the current inrush will weld the contactor closed.

 

[SteelClouds]

I was wondering a lightly different question.. moving from a small pack standard range to extend range pack. I bet that would cause the computer to lose its mind

 

[Nam Nguyen]

Props on buying a salvage Tesla and not being afaid to tear into it. I bought a 2021 salvaged model 3 recently as well and am having fun trying to get it to charge. I have a different issue but my battery is also at 0mi which I am curious to see if this will cause any issues when I do fix the charging issue.

Bump for your answer, hope you are able to figure it out!

 

[Nam Nguyen]

Do you succeed? Are you using tool box 3 to upload the firmware?

 

[Nam Nguyen]

I was wondering a lightly different question.. moving from a small pack standard range to extend range pack. I bet that would cause the computer to lose its mind

Yes computer already lost its mind and I’m finding the way to fix.

 

[Nam Nguyen]

DO NOT apply 12V to the contactor! The BMS has to pre-charge the HV system otherwise the current inrush will weld the contactor closed.

As there will be no load so closing the contactor will just enable the battery voltage through power convertor board. There just be small current flow through contactor. That’s what I think but I’m not sure. I think I should reset alarm/accident counter due to accident sos so it will bring the car back and energize the contactor, won’t it?

 

[smatthew]

As there will be no load so closing the contactor will just enable the battery voltage through power convertor board. There just be small current flow through contactor. That’s what I think but I’m not sure. I think I should reset alarm/accident counter due to accident sos so it will bring the car back and energize the contactor, won’t it?

The capacitors on the motor inverters will charge up.....

from Tesla's Model 3 Theory of Operations document

The drive inverter embeds big capacitors. Any capacitor is like a strong magnet for electrons or current. If empty and exposed to a current, they will suck it in at very high rate.

This is why the pack contactors cannot close directly on the HV bus, the capacitors in the drive inverter would suck in huge amount of current and cause several thousands of amps to rush through he contact bar for the pack contactors. This would cause arcing, potential failure of the pack contactors and damages of the powertrain from the high inrush current.

To avoid this issue, we have a precharge sequence that allows slowly charging up those capacitors.

The precharge mechanism on Model 3 is FUNDAMENTALY different than on Model S and Model X. There is no precharge relay or resistor. Model 3 uses the 12V battery and the PCS to step up the voltage from the 12V battery to match pack voltage. The PCS becomes a key components of closing pack contactors.

 

[Nam Nguyen]

The capacitors on the motor inverters will charge up.....

from Tesla's Model 3 Theory of Operations document

That is very comprehensive reply. Thank you. In my case, I connect to drive unit as well. I would understand with such big inductive load, it required capacitor to compensate the reactive power to run the motor. Yes would be immediately charge the capacitor once the battery contactor is close. Let me try to use the toolbox 3 to synchronize the firmware. Do you know if it will help?

 

[smatthew]

That is very comprehensive reply. Thank you. In my case, I connect to drive unit as well. I would understand with such big inductive load, it required capacitor to compensate the reactive power to run the motor. Yes would be immediately charge the capacitor once the battery contactor is close. Let me try to use the toolbox 3 to synchronize the firmware. Do you know if it will help?

Unfortunately I've Never had the privilege of interacting with Toolbox. I would assume it would handle the precharge sequence just fine. Best of luck!

 

[Jeff_fixin]

Thanks for the shout out! I was able to repair the circuit board and the pictures did help.

I now have 1 remaining fault which I will happily share as I purchased the toolbox 3 software to decipher the codes (faults on the screen are cryptic to say the least). Ignore BMS_a063 as it is just a CP fault, CP_a009 reads "high voltage cover not sensed" which leads me to believe I am just missing a cover. The car came with no cover on the inside, perhaps because it broke in the accident. You have any pictures of what the inside of the charge port looks like and what the p/n is on the cover ? I can only find the previous generation charge port schematics and parts.

 

[Nam Nguyen]

So you use toolbox 3 to deploy the firmware? For the battery cover. Here is the picture with part no for several parts

1476608-00-B
1478844-00-A
1478840-00-A

 

[smhube00]

Jeff
i am trying to fix my gen 4 board too. I am fixing 2020 Tesla 3 LR

can you send me pictures of the back side if you have any

I may need the same piece and some of the small resistors

thanks

 

[Nam Nguyen]

Hi,

I bought a battery 50kWh from one car standard range single motor and the rest from another car LR dual motor.

I use toolbox 3 to synchronize all firmware.

I manage to update the firmware and get software updated.

But still configuration mismatch.

Any one can give advise how I can reconfigure the car configuration to accept new 50kWh battery?

Thank you for your help.
BR, Nam

 

[KenC]

I'd get in touch with Rich Benoit of Rich Rebuilds. He has a youtube channel.

 

[Mapky1]

It is talking about the penthouse cover as there is a ground resistant measurement to ensure that cover is indeed installed to allow startup of HV system. I have internal docs I could share that elaborate this.

Toolbox is great but the codes you specified, you could have just received through the infomat service menu embedded and Jo longer geo fenced to work around service centers!

 

[Nam Nguyen]

It is talking about the penthouse cover as there is a ground resistant measurement to ensure that cover is indeed installed to allow startup of HV system. I have internal docs I could share that elaborate this.

Toolbox is great but the codes you specified, you could have just received through the infomat service menu embedded and Jo longer geo fenced to work around service centers!

Thank you Mapky if it is the way to call you . Appreciate if you would share the document. For the "infomat service menu" here you mean factory mode? You have any idea how to access this mode. If using tool box can only enable the service plus mode.

BR; Nam

 

[Terel]

Hi,

I bought a battery 50kWh from one car standard range single motor and the rest from another car LR dual motor.

I use toolbox 3 to synchronize all firmware.

I manage to update the firmware and get software updated.

But still configuration mismatch.

Any one can give advise how I can reconfigure the car configuration to accept new 50kWh battery?

Thank you for your help.
BR, Nam

Any update? I have the same problem, still mismatch configuration.

 

[Chewyxb71]

It is talking about the penthouse cover as there is a ground resistant measurement to ensure that cover is indeed installed to allow startup of HV system. I have internal docs I could share that elaborate this.

Toolbox is great but the codes you specified, you could have just received through the infomat service menu embedded and Jo longer geo fenced to work around service centers!

Hey Mapky1, I have a 2022 Model S Plaid with similar errors & I also have a toolbox 3 subscription but have not been able to get contactors to stay closed. Would you be able to share those internal docs? Feel free to PM me. Thx!