CAN bus sniffing

[jmp49]

You can hook a arduino up for canbus sniffing too, there's even a canbus module nowadays. I know some people heavily into car hacking using them and more complex micrcontrollers as tooling.
www.instructables.com/CAN-Bus-Sniffing-and-Broadcasting-with-Arduino/

I will have a proper crack at the immobilizer module of the SLK R170, because I see a couple of people in the aftermarket are selling replacement keys now which is supposed to be impossible but charging a fortune and nobody is sharing info, so that it must be possible. If I can break it, after being forced to invest time because of info hoarders I'll put the details on github and the groups, information wants to be free...

Id encourage you to share this wider when your happy with progress, because while a majority of people will just lazy copy and want handholding, you might find the odd person reads and understands the code, and is willing to contribute fixes and improvements that maybe you hadnt thought of or spotted.

 

[m_c]

Impressive stuff. I'd always assumed this level of detail was only available with the professional grade scan tools, which are several times the value of the old snotters I'm usually dealing with. Tempted to have a play myself now. Part of my day job recently is writing code to log realtime data from lab instruments, the learning curve was a lot less painful than I thought.

I've managed up to now with a cheapy Bluetooth OBD adapter and Torque Pro, can't complain about the price but I'd like to understand more of what's going on under the surface and nothing teaches you that like building it yourself.

How much of the protocol have you had to reverse engineer, vs get from paid-for specs, vs get for free online?

What Kayos is doing, is 'sniffing' aka reading data that is routinely transmitted on the CAN buses between modules.

Fault code readers query the modules for data (this may be directly, or via another gateway module already in the car), which allows them to see in more detail what individual modules are doing.
An example would be the ABS/TC module will regularly transmit the vehicle speed to other modules so you can sniff that data, but it likely won't routinely transmit individual wheel speeds, so you need to query the module directly for that data.