OpenHaldex-S3

OpenHaldex-S3 mobile interface and install screenshots

Free and truly open source
DIY Haldex AWD control for compatible VW and Audi vehicles.

OpenHaldex-S3 is a free open-source Haldex AWD controller built for the LilyGo T-2CAN ESP32-S3 board. It supports Gen 1, 2, 4, and 5 Haldex systems with map-based control, web-based setup, live diagnostics, and simple self-installation using inexpensive off-the-shelf hardware.

WHAT YOU NEED

INSTALL OPENHALDEX-S3

CHECK COMPATIBILITY

Easy to build and install in minutes.

Supports Gen 1, 2, 4, and 5 VW and Audi Haldex systems.

If you can wire a light switch, you can build this.

Lift the rear seat, plug it in, and you’re done.

No custom wiring harness. No soldering. No permanent modifications.

What OpenHaldex-S3 Does

  • Direct control over Haldex AWD behavior
  • Mode switching with ESP button (or any button you choose)
  • Speed, throttle, RPM, and map-based locking
  • Gen 5 support with decoded MQB CAN signals
  • One-click calibrate to your Haldex for accurate AWD control
  • Web-based control panel and online firmware updates

Build OpenHaldex-S3 for Under $50

What You Need

  • LilyGo T-2CAN ESP32-S3 board (~$30)
  • OEM VW/Audi Haldex connectors (~$15)
    Gen 1: 1J0-973-714 and 1J0-973-814
    Gen 2-5: 1J0-973-713 and 1J0-973-813
  • Small enclosure (~$10)
  • Small screwdriver
LilyGo T-2CAN ESP32-S3 board used for OpenHaldex-S3
OpenHaldex-S3 hardware and OEM Haldex connectors

Build

To run OpenHaldex-S3, only 6 connections are required:

  1. 12V+ power (12-24V input)
  2. Ground (GND)
  3. Haldex CAN High (CANHA)
  4. Haldex CAN Low (CANLA)
  5. Vehicle CAN High (CANHB)
  6. Vehicle CAN Low (CANLB)

Note: CAN High is Orange/Black and CAN Low is Orange/Brown.
Brake, park brake, and other unused OEM wires should be connected directly together to preserve the original circuit path.

Flash

  1. Connect USB to the LilyGo T-2CAN
  2. Enter boot mode
    Hold BOOT, press and release RESET, then release BOOT
  3. Click Install below for your desired OpenHaldex firmware variant

Install OpenHaldex-S3

OpenHaldex-S3

OpenHaldex-S3 is our custom OpenHaldex build for the LilyGo T-2CAN, created for users who want a more advanced and configurable DIY Haldex controller.

It includes map-based control, advanced settings, live diagnostics, and a web-based setup interface.

OpenHaldex-S3 screenshots and mobile interface

v1.0

OpenHaldex-C6 Option

An additional LilyGo T-2CAN firmware option is also available for installation, OpenHaldex-C6 from Forbes Automotive.

This is provided as an alternate install path for LilyGo users who want to compare firmware options on the same hardware.

Alternative OpenHaldex-C6 firmware interface for LilyGo T-2CAN
Alternative OpenHaldex-C6 firmware setup screen on LilyGo T-2CAN

v3.00.1

OpenHaldex-S3 Setup

  1. Use your phone, tablet, or laptop
  2. Connect to the available OpenHaldex-S3 hotspot
  3. Browse to 192.168.4.1
  4. Configure your setup page
  5. Customize your AWD behavior

OpenHaldex-C6 Setup

  1. Use your phone, tablet, or laptop
  2. Connect to the OpenHaldex-C6 hotspot
  3. Browse to 192.168.1.1
  4. Configure your setup page
  5. Customize your AWD behavior

Compatible Haldex Generations and Vehicles

OpenHaldex-S3 supports compatible Gen 1, 2, 4, and 5 Haldex applications across selected VW and Audi vehicles.

  • Audi A3 / S3 8L Quattro 1998-2003
  • Audi TT 8N Quattro 1998-2006
  • VW Bora 2.8 V6 4Motion 1998-2004
  • VW Golf 1J Mk4 R32 4Motion 1998-2004
  • VW Sharan 7M Phase 1 Mk1 1998-2007
  • VW New Beetle RSi 1998-2003
  • Skoda Octavia 1U 4×4 Mk1 1998-2004
  • Seat Leon 1M Mk1 Cupra4 1998-2005
  • Seat Alhambra 7M 1998-2007

  • Audi A3 / S3 8P Quattro pre-facelift 2004-2008
  • Audi TT / TTS 8J Quattro pre-facelift 2007-2009
  • Volkswagen Golf 1K Mk5, R32, 4Motion 2004-2008
  • Volkswagen Passat 3C, 4Motion, Santana, CC 2005-2009
  • Volkswagen Transporter T5 pre-facelift 2003-2009
  • Seat Altea 2007-2010
  • Seat Alhambra 7M facelift 2005-2010
  • Skoda Octavia 1Z pre-facelift 2004-2009

  • VW Golf Mk6 5K 4Motion 2008-2012
  • VW Golf R Mk6 5K 2008-2012
  • VW Tiguan 2008-2014
  • VW Sharan 7N Mk2 2011-2015
  • VW Passat, CC, B7 2010-2015
  • VW Transporter late-model T5 facelift 2009-2015
  • VW Caddy Mk3 2K facelift 2010-2015
  • Audi A3 / S3 8P facelift 2009-2012
  • Audi TT / TTS / TTRS 8J facelift 2008-2012
  • Audi Q3 / RS Q3 2011-2013
  • Seat Altea XL / Freetrack 2010-2015
  • Seat Alhambra 7N 2011-2013
  • Skoda Yeti pre-facelift 2009-2014
  • Skoda Superb 3T 2008-2014
  • Skoda Octavia 4×4 / Scout / vRS 4×4 1Z facelift 2009-2014

  • VW Golf Mk7 and Mk7.5 R / 4Motion
  • VW Passat B8 / Arteon 4Motion
  • VW Atlas / Teramont 4Motion
  • VW Tiguan
  • VW Sportwagen / Alltrack Golf
  • Audi S3 8V Quattro
  • Audi TT / TTS / TTRS 8S Quattro
  • Audi Q3 F3 Quattro
  • Skoda Octavia 5E 4×4 / Scout
  • Skoda Superb 3V 4×4
  • Skoda Kodiaq 4×4
  • Seat Leon 5F 4Drive / Cupra
  • Seat Ateca 4Drive

  • What is OpenHaldex-S3?
    OpenHaldex-S3 is a free DIY Haldex AWD controller for compatible VW and Audi vehicles. It runs on the LilyGo T-2CAN ESP32-S3 board and supports Gen 1, 2, 4, and 5 Haldex systems.
  • What vehicles are compatible with OpenHaldex-S3?
    OpenHaldex-S3 supports selected VW and Audi Haldex applications across Gen 1, 2, 4, and 5 systems. See the compatibility section above for common supported vehicles.
  • Is OpenHaldex-S3 safe to use?
    OpenHaldex-S3 has been real-road tested for thousands of miles without incident. It installs on the fused OEM Haldex circuit, supports normal vehicle operating voltage (12-24V), and does not modify general CAN traffic or override factory safety systems.
  • Does OpenHaldex-S3 cause warning lights?
    Under normal operation, no warning lights are expected. During aggressive driving, certain settings can trigger a temporary traction control warning. This clears after a key cycle.
  • Is the LilyGo T-2CAN ESP32-S3 suitable for automotive use?
    Yes, for this application. The T-2CAN is a dual-CAN ESP32-S3 board with a 12-24V input stage and has proven stable in real vehicle use as a DIY Haldex controller. Additionally, the dual-core CPU means that important CAN functions are performed independently of busywork, such as wifi, visualizations, etc.
  • Why should I try OpenHaldex-S3?
    Because it is free, easy to build, easy to remove, and built on inexpensive off-the-shelf hardware. It gives compatible VW and Audi owners a simple way to try map-based Haldex control without buying dedicated aftermarket hardware first.
  • What if I do not like OpenHaldex-S3?
    That is fine. It can be removed by unplugging it, and you still have a LilyGo T-2CAN development board.