The original and official OpenHaldex, by Forbes Automotive
Complete control over your Haldex AWD system
OpenHaldex is the official open-source controller for Haldex all-wheel drive on Volkswagen, Audi, SEAT and Škoda. Six drive modes, live data and Wi-Fi setup from your phone, or tune your own lock map against speed and throttle.
Designed and maintained by Forbes Automotive. For enthusiasts – by enthusiasts.
A small box between your car and the coupling
The Haldex coupling decides how hard to clamp its clutch pack based on messages it hears on the CAN bus. OpenHaldex sits in that conversation. It reads what the car is saying, changes the parts that matter, and passes everything on.
In Stock mode nothing is changed and the car behaves exactly as it left the factory. Pick any other mode and the coupling gets the lock you asked for, every time.
It runs on your car's own CAN signals, or in standalone mode with no chassis bus at all, which makes it a good fit for engine and drivetrain conversions.
Six modes, selectable on the move
The same six modes you see in the controller’s Mode Selection panel. Switch from your phone, from the button on the unit, or wire in your own dash button.
- Stock
Passes factory Haldex control through untouched.
- FWD
Holds the coupling open for front-wheel drive — less drivetrain drag, better economy, perfect for burnouts!
- 50:50
Maximum engagement for traction off the line, on track, in snow or off road.
- 60:40
A measured amount of rear drive with a front bias — stable and predictable on the road.
- 75:25
Just enough rear assistance to settle the car without the drag of full engagement.
- Expert
Define your own engagement behaviour against speed and throttle for a bespoke setup.
Built for enthusiasts, by enthusiasts
Everything the controller does is open-source and yours to change.
- OPEN
Open-source firmware
All firmware, documentation and reference designs live on GitHub. Read it, build it, improve it.
- WI-FI
Wi-Fi configuration
The ESP32-C6 hosts its own web interface. Change modes and settings from your phone’s browser. No app or cable required.
- LIVE
Live data & diagnostics
Speed, throttle, RPM, boost, Haldex engagement, clutch reports and temperature protection, all in real time.
- OTA
Over-the-air updates
New firmware installs from the controller’s own interface, or over USB straight from your browser.
- BUTTON
Physical mode control
Cycle modes from the button on the controller, or force modes using dash buttons.
- STANDALONE
Standalone operation
Runs without an ECU when you need it — useful for swaps, custom builds and bench work.
Fitting it
The optional harnesses mean no cutting or soldering, and everything comes back out just as easily.
Generation 5: plug-and-play, in minutes
- Lift the rear seatThe Haldex connector sits underneath.
- Split the factory connectorUnplug the factory Haldex plug.
- Plug in the harness and controllerThe harness goes in between; the controller clips onto it.
- DriveJoin the
OpenHaldex-C6Wi-Fi and pick a mode.
Generation 1 to 4: one harness for all four
The connection is at the Haldex coupling, so this one means working under the rear of the car. The harness plugs in at the coupling and runs back through the factory grommet into the boot floor, where the controller is mounted.
Supported Haldex systems
Most Volkswagen, Audi, SEAT and Škoda models built with Haldex four-wheel drive.
| System | Platform | Status |
|---|---|---|
| Generation 1 | PQ | Supported |
| Generation 2 | PQ | Supported |
| Generation 4 | PQ and GM | Supported |
| Generation 5 | MQB (0CQ) and PQ (0AY) | Supported |
| VAQ | MQB | Supported |
| Generation 4 Ford | Ford | In development |
| Generation 3 | Volvo | Not supported |
Build it or buy it
Every schematic, Gerber and line of firmware is on GitHub under the MIT License. If you'd rather not build one, Forbes Automotive sells them assembled and tested.
Questions
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).
Join the Discord
Get help with installs, share logs and builds, and hear about new firmware first.