Tinkering with your vehicle’s Controller Area Network (CAN bus) can be risky, potentially causing damage or unintended vehicle operation. Therefore, attempting this project is at your own risk, and no guarantees are provided. It is highly recommended to start experimenting while your vehicle is safely PARKED. If you are unfamiliar with any part of these instructions or the code involved, it’s advisable to avoid working with your car’s electrical system. For a safer and simpler alternative, consider using a pre-made Bluetooth OBD dongle instead. Proceed with caution and good luck.
With the necessary disclaimer addressed, let’s delve into the world of CAN bus. If “CAN” sounds similar to terms like LAN (Ethernet) or WLAN (WiFi), it’s because they are all types of networks. CAN, or Controller Area Network, serves as your car’s internal communication system. Instead of relying on direct wiring from the engine computer to every sensor, light, and device, modern vehicles utilize this digital network for control and communication.
The CAN bus operates on a differential communication protocol, requiring only two wires for operation. Unlike traditional serial communication with Tx/Rx lines, CAN bus facilitates communication without direct device-to-device transmission. Typically implemented as a twisted pair of wires throughout your vehicle, access to the CAN bus is conveniently available through the OBD port. While a deep understanding of the protocol’s intricacies isn’t essential, a working knowledge sufficient for modifying Arduino code is necessary for this project.
To proceed with this guide, ensure your vehicle is equipped with a CAN bus. Virtually all vehicles manufactured today feature an OBD II port, standardized with the same electrical connector located under the dashboard. However, communication protocols can vary significantly depending on the auto manufacturer. Vehicles sold in the United States post-2008 commonly utilize the ISO 15765 CAN bus protocol, which is the focus of this project. Verify that your vehicle employs a CAN bus system. Remember, each car is unique, possessing specific CAN bus speeds, OBD codes for data requests, and individual characteristics that may require adjustments during implementation.
