How to Make a VAG-COM Cable
by Deborah GrayTo use the VAG-COM Diagnostic System by Ross-Tech, a PC to OBD-II cable is required. VCDS is used to interpret on-board Volkswagen diagnostics in more specific detail than generic OBD-II software packages do. It can also be used to interpret generic diagnostic codes from cars by other makers.
You can make a generic interface cable that connects the PC to the car's on-board diagnostics outlet. The end of the cable that connects to the car will use an OBD-II connection, while the PC end will connect via universal serial bus, or USB.
Step 1
Cut the 4 wire USB cable to the desired overall length up to 9 feet using the wire cutting tool.
Step 2
Remove 1 inch of the outer insulation on each end to reveal the 4 wires inside. If there is a metal braided sheath protecting the inner wires, fold it back away from the inner wires.
Step 3

Remove 1/2 inch of the insulation from the tips of the 4 inner wires, leaving the copper wires exposed.
Step 4
Thread the exposed inner wires on one end of the cable into the USB connector in pin-out order. Solder the wires firmly into place and attach the outer jacket.
References
Things You'll Need
- 4 wire USB cable
- Wire stripping and cutting tool
- USB connector
- OBD-II CAN connector
- Soldering iron and solder
Writer Bio
Deborah Gray has been a technical writer in the information technology industry since 1987, including 15 years with Hewlett-Packard. She has authored numerous guides, white papers, presentations, training courses and technical articles. Gray became an HP-certified consultant in 1997. She holds a B.A. in computer science and business administration from Anderson University.