Arduino - Adafruit CAN Bus Shield

Hey everyone, let me introduce myself briefly:

I am Marc, 30 years old, and I am from Wertheim am Main.


I'm currently working on connecting my Mercedes W204 to an Arduino using an Adafruit CANBus shield.

Can someone help me figure out how to read the CAN bus messages from the steering wheel buttons, such as those for volume up (+) and volume down (-), etc.?

Best regards,
Marc

You need a CAN-Bus interface for your laptop to read the data. This allows you to monitor CAN IDs. With the Arduino, you can then send commands that you, for example, have intercepted and programmed. I'm working on it right now.

Hi,

I can only agree.
You'll get along well with an Arduino if you know which ID you need.
But trying to find a specific message is like searching for a needle in a haystack.

And the Canhack interface continues to impress me.
Every byte is displayed in all possible encodings, and what's particularly noteworthy is that each byte is visualized using a bar.
This way, you can immediately see the bytes that contain counter data (e.g., consumption) versus the bytes that contain sensor data.

I was just looking the other day to find out where the information about "cruise control activated" is displayed.
Using the VCDS diagnostic tool, I saw that this information is only available from the engine control unit.
And then I looked at the individual addresses from the MSG and quickly found the bit in its binary representation.

It's really a wonderful investment if you're planning to do something like that.

Best regards,
Werner.

Hello everyone,
Has anyone had success using an Arduino to actively send data, particularly to Mercedes vehicles?
Thank you and greetings.

Hello Samquadrat,

I have already successfully sent speed and RPM data from an Arduino to a tachometer via the CAN bus in my test setup. However, it's not in a real vehicle, and it's not a Mercedes.
But if you send the correct IDs, it will definitely work. However, you should know exactly what data you are sending in a vehicle. Ultimately, you could disrupt the entire communication process. The lower the ID, the higher the priority. Constantly sending such a message would cause collisions and would make all other devices wait.

Okay, then I'll identify which bus the control units are connected to and trace the signals.