E-tron HVJB

[RetroZero]

Hi there folks,doing a breakdown of an E-Tron HVJB.
It has an isolation fault (intermittantly), so hope the tear down reveals something.
In any case, I hope this helps with overall builds.
The unit weights about 15kgs!
It contains 4 HV ETE Relays
There are 3 main HV Fuses
There is an internal control unit monitoring various HV values and controling precharge relay
There is another circuit board connected directly onto MainPositive HV Relay.
There ia an added junction for what I am yet to confirm is for the Rear Inverter/motor.
There is also another junction for the PTC, AC and Charger - again to be confirmed.
I hope to locate the Pyrofuse to understand the safety circuits better too.
Enjoy

[EV_Builder]

Any chance you make a zoom picture of that square ic on first & second picture; off the current sensor and hv sense board?

[RetroZero]

Decided to remove the sensing board. Hope the pictures make sense. Would this be audi's version of isabellenhutte?

[EV_Builder]

Can you read the "middle" chip? and post it here? i miss a tiny bit to read it.

[RetroZero]

So , out with magnifying glass and cross eyes
These are references for sensing board.
On a side note, this board connects to the 'main internal board' which will be in the next post.
Is this some overkill, or just how important voltage sensing, isolation and contacter controle is?

[RetroZero]

This is the main contacter controle board inside the HVJB.
It has 10 wires from the outside world, 2 of which are CAN

[EV_Builder]

Is this some overkill, or just how important voltage sensing, isolation and contacter controle is?

I think both is true, but one wants high safety standards.

[RetroZero]

Did some poking about with a multieter and marker pen. Some interesting findings.
There are 2 circuit boards monitoring various voltages before and after the 4 HV Contactors.
Since there are 2 inverters/motors, there's lots of doubling up I imagine.
What is most interesting is the "Bridge Board" before Main Positive HV Relay. It seems to have a circuit to monitor isolation/current, as there are 2 sets of wiring going to the Main Board. There is also a "copper bar" welded between 2 bus bars with Tabs that are connected to the circuit board.
I would like to find out how HV Isolation is calculated, as it is a requirement for my build I would need to intergrate. Time for Wiki and Google

[RetroZero]

Some more useless info, the main circuit board also has the function of PWM signals to keep the HV Relays closed.
If we want to re-use these contactors, we need to have PWM wizardry as well.

[Mitchy]

Hey Retro.

Do you happen to have any part# for the two HV plug connectors on the front of the unit? (The large ones)
Or if you’re scraping the unit, I’ll be interested in buying them both from you.

[RetroZero]

Sorry just saw your message. Will have to look into it next week. I'm out of town for the moment.

[Mitchy]

Hey, No worries. Found them once my Taycan charger port arrived.
They're Rosenburger HVR420's
https://www.rosenberger.com/product/hvr420/

[RetroZero]

I'm getting a few bits together to set myself CANning thanks to @gregski and his CAN thread so will be following your progress. Hope to copy off as much of your work to get a VW charger functional. Let me know if you still would like those hv connectors.

[RetroZero]

So now that I have SavvyCan running, I hooked up firstly the SX6 main board, which swithes the various HV relays, and then the Shunt board which measures Isolation. Using the Fuzzing mode, I managed to get a few ID's out of them. I hope they can be some use to us for decoding....
Please let me know if this helps in any way, or what I should be logging.

[dzhiday]

It has an isolation fault (intermittantly), so hope the tear down reveals something.

Hi. Did you solve the problem with isolation fault ?
could you share the results?
what components and on which board need to be replaced?

[RetroZero]

Sorry, everything in boxes,as I am trying to sort out a workshop. Do you have one available?

[dzhiday]

Sorry, everything in boxes,as I am trying to sort out a workshop. Do you have one available?

I have one etron with a BIG RED message "electric system malfunction" on the dashboard and error code P0AA700 (isolation fault) in DTC...
The error appears only when is cold outside (less than 5°C).
and so I'm looking for ways to solve this problem.

[RetroZero]

Remove each high voltage component one by one, erasing the fault each time until it's not present anymore. Do you have a way to capture some logs?