Frequently asked questions
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Is this the official OpenHaldex?
Yes. openhaldex.com is run by Forbes Automotive, who created OpenHaldex-C6 and reverse-engineered the Generation 2, 4 (including GM) and 5 Haldex logic it's built on. Other projects using the OpenHaldex name or code aren't the work of Forbes Automotive and can't be supported by us. Official firmware lives in the Forbes-Automotive/OpenHaldex-C6 repository.
What vehicles does OpenHaldex work with?
Volkswagen Audi Group cars with Generation 1, 2, 4 and 5 Haldex couplings: PQ-platform cars (Gen1, Gen2, Gen4 and Gen5 0AY) and MQB cars (Gen5 0CQ). It also supports the GM version of Gen4 and VAQ. Generation 3, which was used by Volvo, isn't supported. See Compatibility for the full list.
What does OpenHaldex actually do?
It sits between your car and the Haldex controller on the CAN bus. In Stock mode it passes messages straight through, so the car behaves exactly as it left the factory. In any other mode it adjusts the messages to request the amount of clutch lock you've chosen, from zero (front-wheel drive) to full lock, or a lock map you've tuned against speed and throttle.
Can it send more than 50% of the torque to the rear?
No. Haldex is a front-biased system: the front axle is driven directly by the gearbox, and the coupling can only add drive to the rear. At full lock the split is roughly 50:50. That's true of every Haldex controller, not just this one.
Is OpenHaldex an official Volkswagen or Audi product?
No. OpenHaldex by Forbes Automotive is an independent, open-source project and is not affiliated with, endorsed by, or sponsored by Volkswagen AG or any of its brands.
Can I install it myself?
Yes. On Generation 5 cars the plug-and-play harness makes it a few minutes' work under the rear seat. Generations 1 to 4 share one harness that connects at the Haldex coupling, so it means working under the car and routing the harness into the boot. Without a harness you build a short Y-branch loom yourself; the pinouts are on the Install page and in the installation guide (PDF).
Will it flatten my battery?
Not when it's set up properly. On a permanent 12 V feed it shuts its Wi-Fi down after five minutes of no activity, and with CAN Sleep enabled it drops to about 14 mA while the car is parked. It wakes the moment the car does. See Low Power Mode.
How do I connect to it?
Join the Wi-Fi network called OpenHaldex-C6 from your phone, then open 192.168.1.1 or openhaldex.local in a browser. The network is open by default; you can set a WPA2 password from the Diagnostics page.
I've forgotten the Wi-Fi password. What now?
Long-press the Mode button on the controller. That clears the password and restarts an open access point. Your network name is kept.
How do I update the firmware?
On current firmware, from the controller's own OTA page over Wi-Fi: upload littlefs.bin, then firmware.bin. For a first install or recovery, plug it into a computer with a USB-C data cable and use the firmware updater in Chrome or Edge on a desktop. Export a backup of your settings first.
Will VCDS or ODIS still work with it fitted?
Yes. Live Diagnostics uses the same diagnostic channel as a scan tool, so it switches itself off when it sees VCDS, ODIS or similar. If a scan tool still won't connect, turn Live Diagnostics off in Settings.
Is it open source?
Yes. The firmware, schematics, PCB layouts, Gerbers and enclosure files are all on GitHub under the MIT License. You're free to build, modify and redistribute it. Just keep the copyright and licence notices.
Is it road legal?
OpenHaldex changes how your drivetrain behaves and is intended for off-road and closed-course use. It can increase drivetrain wear. Use it at your own risk.