Tesla Model 3 Rear Drive Unit Hacking

[davefiddes]

Congratulations on getting your motor running!

The oil pump behaviour is concerning. At the moment the code is utterly minimal and just sets the pump to run at a fixed speed irrespective of operating mode, temps, motor rpm, etc. If LIN bus comms are working as you describe but the pump speed can't be changed then that implies that I'm not sending the right command PID for your oil pump or the PID is not correctly formatted. The pump goes into full blast limp home mode if you don't send the correct command PID for a second or two.

Edit: Would it be possible to get a LIN capture from your Tesla inverter PCB? It doesn't need much in the way of equipment just a Saleae Logic compatible logic analyzer (the cheap $10 clones from ebay are fine) and a potential divider to take the 12V LIN signal down to something that won't blow up the analyzer (say 33k and 10k). The Tesla firmware sends LIN requests out all the time and doesn't need the pump connected. Let me know if you need more details.

The Tesla firmware sends out a single command on PID 0xA and requests status on PIDs 0x2A, 0x30, 0x31 and 0x32.

[nathaniel]

I have a lin logger tool, never used it but i guess now is the time te try it out. I have also a picoscope or a digital scope that can decode lin so i give that a try.
Also I have a older model 3 motor, the 3D5 so i can plug that oilpump in and see what that is doing.
Also try the new parameters from Demian and report back my findings. I hope that i can do it tomorrow but otherwise i have friday some time to test it. I'll keep you posted. Thx for the feedback

Edit: for the syncoffset I run the "default" 34968 and that is working, so it looks like they aligned the resolve nicely with the motor stator. And the 3d7 motor has no wire windings bus flat bars instead. But looks like the resolve alignment it's still the same.

[davefiddes]

I have a bit of confusion about the current sensors. I bought MLX91209LVA-CAA-000 parts which are set to 50mV/mT sensitivity as that was what was listed on the schematic. I note that the install video (and now wiki) lists MLX91209LVA-CAA-002 as the part which is the 7.3mV/mT sensitivity variant.

Which of these is correct and how do we know this? The devices are not marked with what they are programmed to.

Technically the current sensors are programmable but this only appears to be possible with a $1000 programmer with a $200 adapter.

[johu]

The Tesla SDU inverter uses 7.3 mV/mT, so quite probable this one does, too

[Jack Bauer]

You can use almost any version Dave and just change the calibration parameter. Back a few years ago I compared the sensors in the SDU to a bunch of variants and found the "Tesla" version was bang on 7.3. I've not done so as yet for the M3 but will do when I have the next batch of boards as I have a front drive unit inverter that is still standard. I'm finding the transistors will desat at between 800 to 900A in any event. Sorry for the confusion.

[davefiddes]

Ah. Thanks for the background. It makes sense they would keep things the same.

I have the bits so I was going to try to get at the leadframe and resurrect one. It should be possible to compare both sensors for science.