CAN BUS tester

Good day,

Please forgive me if this has been discussed before.

I am a complete newbie to arduino and programming.

I want to build a simple automotive can bus tester where i would be able to connect the canH and canL and verify that the can bus is working.

So I was thinking to use the arduino uno/mega with a can bus shield and a LCD to display the canH and canL data. Just 1 line of each will verify the can network in working. I will be able to test various points on a vehicle to isolate a can bus wiring fault (this is common on heavy duty vehicles)

Is this possible?

What are your suggestions on the shield to get?

Will this work on basically any can bus ?

I know there are tools out there that can do this but I want to build this to learn more about Can Bus networks on cars/trucks/rigs etc. I am looking at this as my first step in understanding can bus.

Thank you all.

Hello RaceShop,

Your idea is doable. To start I do recommend you get for your self:

Now the first step is to make one Arduino talk to each other, to prove everything is working. You'll need to grab a library, like this one: GitHub - Seeed-Studio/Seeed_Arduino_CAN: Seeed Arduino CAN-BUS library - MCP2518FD&MCP2515&MCP2551

Once you have one the receive_check on one node and send or send_blink on the other node and things seems to be working you can try to build your own code. I would suggest to use the Serial console first to later add the LCD screen. This makes the development in "baby-steps" easier... Also, make sure you have a way of switching the CAN Speed as the Speed of your diagnostic "board" needs to match the same in the vehicle. Maybe a button that switch the speed and restart the monitoring.

Well, that's already a good starting point... once you progress you probably will have other questions.


Thank you very much for your advise. highly appreciated.
I have ordered the arduinos and shield, just waiting for delivery now
cant wait to get started :slight_smile:


I know it has been a year, but i am working on a similar project, and i have been using that library, but it does not work on my board, when i upload it. It keeps saying "init fail" in the serial monitor. did you have this problem?