CAN Bus: How does it work? Sniffing CAN Bus IDs

Fundamentals of the CAN Bus:
https://www.obd.wiki/can

Bit rates and maximum cable lengths:
10 kbits/s: 6.7 km
20 kbits/s: 3.3 km
50 kbits/s: 1.3 km
125 kbits/s: 530 m
250 kbits/s: 270 m
500 kbits/s: 130 meters.
1.0 Mbits/s: 40 m

CAN Interface Hardware with KCANMonitor Software (CAN Bus Sniffing Tool):
https://shop.dieselschrauber.org/en/can-usb-interface-kit-p-313.php

Training on CAN-Bus topics:
https://shop.dieselschrauber.org/en/diagnose-support-c-40.php

Low-Speed CAN, Transceiver, Functionality, Application Tips:
https://www.nxp.com/docs/en/application-note/AH0801.pdf

How a High-Speed CAN Works:
https://www.ti.com/lit/an/slla270/slla270.pdf

Determining the bitrate on a CAN bus is relatively straightforward using an oscilloscope, especially for unusual bitrates.
- Finding the minimum width of a level change.
- Measurement using the cursor.

Where and how can I access the CAN bus?

For some models (e.g., Ford), the CAN bus connection is located on the OBD2 diagnostic connector at the standard pins.
In most vehicles (all Audi, Seat, Skoda, and VW models), the CAN diagnostic interface connected to the OBD2 port is essentially inactive on its own.
The best place to get the wiring diagram for the vehicle is from Erwin (siehe Fehlerdatenbank), and then you can connect to the desired CAN bus at the CAN gateway, where all the CAN buses converge.