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 :dunno:

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.

OK, so you are getting something on the screen just not the data. Is the dashboard app(program) known to work with the CAN module that you have? Have you checked the source code for parameters to be set? Do you have a scope or any way to verify that you have data on the bus or coming from the CAN bus module?

Yes, this was actually the one most users recommend as being compatible with everything. The HAT requires some setup in the boot config files but mine are consistent with everyone else's known working configs, which don't seem to take much else into consideration (like the car transfer speed). Unfortunately I do not have another way to see if I have data coming from the module. Most people had said the best way to ensure your config would be to have gotten the 2 CH module and wire them together and send data from one, to be read by the other.

Is there maybe a ground required from the car to the CAN bus module that you are missing?

I use Phytools PEAK PCAN adapter on all my CAN sniffing projects. It gives me all the information on the bus like CAN addresses, baud rate, etc. It even allows CAN message transmitting to test issues you have.

https://phytools.com/products/pcan-usb-adapter

https://cdn.shopify.com/s/files/1/00...g?v=1569234442

I’m not sure, I will take a look at the pinout, and do some probing to ensure that the ground pins are actually connected to the vehicle ground.

I will look into this, thanks for the tip!