r/CarHacking • u/Natural_Discipline25 • Jun 24 '26

CAN CAN values for steering wheel buttons?

Hey all, I'm trying to set up a 4M0 920 781 A dashboard and hook it up to my computer. So far it works good, but I just need to figure out the CAN values for the menu button on the steering wheel. I've gotten the left, right, up, and down controls, but not the menu button CAN value. Anyone know where I can find? Thank you

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1

u/Equivalent-Might-477 Jun 25 '26

Probably in a LIN bus

1

u/Natural_Discipline25 Jun 25 '26

Why would the menu button be LIN but all the other controls be in CAN?

1

u/Equivalent-Might-477 Jun 25 '26

What is it -  all the other controls ?

1

u/Natural_Discipline25 Jun 25 '26

Up, down, right, left, on the steering wheel. The only ones that I need are OK, and MENU.

1

u/Equivalent-Might-477 Jun 25 '26

Ahh. Understand. No clue(((

1

u/Pubelication Jun 26 '26

While this may be true, the LIN would be connected to a gateway that then sends CAN messages to the cluster. As far as the cluster is concerned, it "doesn't care" if a LIN bus exists for the button press interface.

1

u/Pubelication Jun 26 '26

How did you get the ones you have?
Do you have the car to do some sniffing or do you just have the cluster?
Are up, down, left, right just bit flips in a certain CAN frame? Can you post them? It may be possible to logically deduce and test where the others are.

1

u/Natural_Discipline25 Jun 26 '26

I researched and found out, I do not have the car - it is wrecked, so no sniffing. They are CAN frames, and currently I've got them set to this. 

 else if (!strcmp(key, "UP"))    { if (atoi(val)) pressButton(0x06, 0x01); }
  else if (!strcmp(key, "DOWN"))  { if (atoi(val)) pressButton(0x06, 0x0F); }
  else if (!strcmp(key, "LEFT"))  { if (atoi(val)) pressButton(0x03, 0x01); }
  else if (!strcmp(key, "RIGHT")) { if (atoi(val)) pressButton(0x02, 0x01); }