CAN Bus Interpretation

[Thaniel]

Baud rate for the PT-CAN bus (only CAN bus in an E53, I expect) is 500k.



What do the wires you connected to attach to?


CAN bus wires are twisted pair. For the E46 and similar vehicles (probably E53) it is yellow/brown and yellow/red or something very similar. Might be good to check a wiring diagram. It should clear it up. Careful with yellow wires as yellow is often used in airbag systems. Don't randomly try wires. Also CAN bus is 5V or less. Tapping a 12V wire could have bad consequences.


Make sure CAN H and CAN L are not reversed as well.

[Clavurion]

Behind glovebox sounds like body module (GM3).

On GM3:
*Yellow/black - rear lid (bottom) unlocking
*Yellow/brown - drive rear lid (top)

[lkv0315]

Originally Posted by Clavurion

Behind glovebox sounds like body module (GM3).

On GM3:
*Yellow/black - rear lid (bottom) unlocking
*Yellow/brown - drive rear lid (top)

After a brief google search, that would be the one. Makes sense why it wasn’t doing anything hah.
Is there a cable grommet on the passenger side to pass wires thru to the cabin?

[gpeterson]

The CAN interface you are using has a termination resistor. That may be one of your problems.

https://www.waveshare.com/w/upload/1..._Schematic.pdf

You should look at WDS for pinouts before hooking things up.

[80stech]

Are you running the display with a serial channel? Does the library for the canbus module have some test and diagnostic routines?

[lkv0315]

Originally Posted by 80stech

Are you running the display with a serial channel? Does the library for the canbus module have some test and diagnostic routines?

I’m not sure about the display, but it’s on the miniHDMI if that says anything. There are two test routines that display the raw data that’s coming in on the CAN lines, but I’m not sure about how to test if the setup is correct

[80stech]

If you are using a sketch to run the display and a different sketch for the CANbus then there could be conflicts between the two. Have you done other projects using the display? Does it show anything from the CANbus sketch? Again I'm talking Arduino so what I'm saying might be completely out to lunch for the Pi. What kind of display are you using btw?

[lkv0315]

Originally Posted by 80stech

If you are using a sketch to run the display and a different sketch for the CANbus then there could be conflicts between the two. Have you done other projects using the display? Does it show anything from the CANbus sketch? Again I'm talking Arduino so what I'm saying might be completely out to lunch for the Pi. What kind of display are you using btw?

I’ve never had issues with anything else that worked through the GPIO in regards to the display. I’m not exactly sure what you mean by sketch, but I know that the I/O lanes for the first HDMI port are not shared with anything else. I’m using my Kenwood headunit in “mirror” mode which I assume is for phones but it’s what the HDMI port on the back connects to so

[80stech]

Can you get the Pi to display anything on the head unit? Maybe the problem is more to do with not displaying data more than not reading it. Sketch is what we call the program we upload to the Arduino to run. What do Pi people call it?

[lkv0315]

Originally Posted by 80stech

Can you get the Pi to display anything on the head unit? Maybe the problem is more to do with not displaying data more than not reading it. Sketch is what we call the program we upload to the Arduino to run. What do Pi people call it?

Okay now I get what you mean by the sketch thing. RPi’s are fully fledged Debian Linux single-board computers, so as long as you have proper libraries and support, most Unix programs can run on it, like in this case the apps are .sh or shell files. Yeah I get the desktop and a shell where I run the diagnostic commands and the open source dashboard program as well. The program just says “data: can0. Polling… “ and a blank screen where it should display the hex values.