OpenHaldex-S3 Build Guide

Bill of materials

1. Tools required: flat screwdriver, wire stripper.
2. LilyGO T-2CAN ESP32-S3 board.
3. VW connector with wires 1J0-973-713 (to Haldex).
4. VW connector with wires 1J0-973-813 (from vehicle).

Critical wiring notes

• Use 0.5mm wire for 12V power and ground lines.
• Keep CAN H/L as twisted pairs for noise resistance.
• Double-check connector orientation and pin numbering vs your car's connectors.
• OpenHaldex does not interrupt brake or handbrake lines.

OpenHaldex-S3 Wiring Guide

Haldex connector (VW 1J0-973-713)

1. 12V power -> LilyGO 12-24V (BK/VI)
2. Ground -> LilyGO GND (BR)
3. Brake -> Vehicle Connector Brake
4. CAN L -> LilyGO CANLA (OR/BR)
5. CAN H -> LilyGO CANHA (OR/BK)

Vehicle connector (VW 1J0-973-813)

1. 12V power -> LilyGO 12-24V (BK/VI)
2. Ground -> LilyGO GND (BR)
3. Brake -> Haldex Connector Brake
4. CAN L -> LilyGO CANLB (OR/BR)
5. CAN H -> LilyGO CANHB (OR/BK)

Summary: both connector 12V+ wires join to LilyGO 12-24V, both grounds join to LilyGO GND, chassis CAN goes to CANHB/CANLB, Haldex CAN goes to CANHA/CANLA, and brake lines are bridged.

OpenHaldex-S3 Installation

1. Web Installer

First power-on checks

1. Power the unit and verify it boots without reset loops.
2. Connect via AP or STA, then open http://openhaldex.local (or AP IP http://192.168.4.1).
3. Confirm Setup mapping, diagnostics telemetry, and CAN activity before driving.
4. Start with conservative settings and validate behavior in low-risk conditions.

Related pages

• Getting Started
• Operations + Release
• UI Page Guides
• API Endpoint Reference

Try the OpenHaldex Firmware Demo

Preview the real OpenHaldex firmware UI in your browser with simulated live CAN traffic and interactive pages for tuning, diagnostics, logs, setup, and OTA workflows.

Open firmware demo