About OpenHaldex

Haldex control shouldn't be a closed box with a high price. OpenHaldex is open, inspectable and built by enthusiasts.

Where it started

Years ago a community developer known as A Banging Donk showed that Haldex couplings could be controlled openly. His original OpenHaldex, built on a pair of Arduino boards and later a Teensy, worked on Generation 1 cars.

That proved the idea, but it didn't help owners of later cars. Newer Haldex generations use different messages, different control logic and different diagnostics.

Forbes Automotive took the project on and reverse-engineered Generations 2, 4 and 5, including the GM variant of Gen4. OpenHaldex-C6 is the original source of that Gen2, Gen4 and Gen5 logic. The hardware moved to the ESP32-C6, which added Wi-Fi setup from a phone. Today there are hundreds of controllers fitted to all sorts of builds.

Everything stays open source. If you'd rather not build your own, Forbes Automotive sells controllers assembled and tested.

A lowered burgundy Volkswagen Golf Mk4 on white multi-spoke wheels

What we care about

  • Transparency

    You can read every line of code and every trace on the board. Nothing is hidden behind a licence key.

  • Accessibility

    Performance doesn't need to be expensive or complicated. Build one yourself for the cost of parts, or buy one ready to fit.

  • Maintained

    Releases are versioned and documented so you can rely on them over time.

  • Community

    Anyone can contribute, and improvements are shared and reviewed in the open.

  • Real cars

    Developed on real vehicles and tested against VCDS, not just on the bench.

Credits

  • A Banging Donk for the original OpenHaldex for Gen1 cars.
  • Chris (meatro) for OpenHaldex-S3. Parts of the map editor, CAN view, web interface, PlatformIO structure, API control and SavvyCAN tooling come from it.
  • Arwid Vasilev for the V1.02 PCB redesign.
  • LVT Technologies for the original over-the-air update integration.
  • Everyone who has sent logs, tested betas and reported issues.

Licence

OpenHaldex-C6 firmware and hardware design files are released under the MIT License. Use it, build it, modify it and share it. Just keep the copyright and licence notices.

Other projects built on or copied from this code aren't the work of Forbes Automotive, and can't be supported by us. For official releases, hardware and documentation, use openhaldex.com and the OpenHaldex-C6 repository.

Get involved

Report issues, suggest features or share your CAN logs on GitHub and Discord.