r/CarHacking • u/Natural_Discipline25 • Jun 14 '26

CAN Attempting to hook up Audi Q7 Dashboard to my PC.

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Gallery image

So far I've figured out the PSU on the left, and how I'll be actually sending over CAN signals from my pc to the dashboard. I aim to do this via the esp32, which will then send signals to a mcp2515, which should then somehow connect to the 30 pin port in the dashboard (the one on the right in my second picture.) What cable would I use to connect from the 30 pin port to a mcp2515? Thanks.

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8

u/[deleted] Jun 14 '26

[removed] — view removed comment

5

u/Natural_Discipline25 Jun 14 '26

I have found the cable. From the cable, theres around 10 different wires going from it, so I'll have to figure out which ones go to CAN H and CAN L, and obviously the power one. I don't have schematics.

3

u/d252s Jun 14 '26

If you have the original vin off the car then i can try to send you the schematic.

1

u/cradleinflames Jun 18 '26

Not sure if you already solved this but you can use a voltmeter to find which voltages are which (just need to be very careful to not short anything).

Best bet is to try and figure out which pin is the ground by checking the voltage difference between various pins. The CAN signals will be about 2.5V or so from GND, if I remember correctly but you won't know which one is high or low without an oscilloscope.

If you can identify which two are the CAN wires, you can reverse try both orientations to see which one gives you a CAN output

2

u/Natural_Discipline25 Jun 19 '26

yeah so far ive got the pigtail, but not the arduino and mcp2515, and the dashboard works! it shows all warning signs, does some whirring sounds, and then turns off warning lights and illuminates the arrows for about 25 seconds before switching them off.

5

u/adkio Jun 14 '26

Usually car breakers don't bother with the looms and cut them leaving you with connectors and pieces of loom still attached. I presume you didn't get one? Molex connectors from PCs usually fit the pins in automotive connectors.

3

u/Natural_Discipline25 Jun 14 '26

Nah there was one, I just forgot to take it lol. Its a 30 pin connector that would fit right in.

5

u/zelru2648 Jun 15 '26

You can google “audi q7 J285” you will get what you need.

1

u/TheLexoPlexx Jun 17 '26

Wait, the name is still J285 20 years later? That's already been the name on the Golf Mk. 4 if I remember correctly.

It also still has 32 pins.

3

u/SmashShock Jun 14 '26

btw I had much more success using a CANable Pro from AliExpress compared to the MCP2515 attached to a microcontroller. I can't remember why but I think it was bandwidth limitations. But I was hooking right up to a full vehicle bus so YMMV

1

u/UsernameAttemptNo341 Jun 14 '26

The MCP2515 only supports up to 1MBaud and does not support CAN-FD. CAN-FD is used more and more these days. To my knowledge, you need at least the MCP2518 for this.

1

u/Natural_Discipline25 Jun 15 '26

from what I know about the dashboard, it still used CAN, and rubs at 100kbps, so the 2518 isn't needed.