How to Make a VAG-COM Cable

by Deborah Gray

To 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

Using a wire cutter prevents damage to the cable.

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.

Solder attaches the wires to the connector.

Thread the exposed inner wires of the opposite end of the cable into the OBD-II CAN connector. Follow the same pin-out order as was used for the USB connector, with the same color wires for the data, ground and vbus. Solder the wires firmly into place and attach the outer jacket.