From m.y. 2001:

Connect VAS 5051 tester to DLC using adapter cable VAS 5051/1 and K-wire adapter cable VAS 6017.

Fig 1: Connecting Scan Tool To DLC (Through Model Year 2001)

Courtesy of AUDI OF AMERICA, INC.

Optional: Connect VAG 1551 or VAG 1552 Scan Tool (ST) to DLC using VAG 1551/3 adapter cable and k-wire adapter cable VAS 6017.

WARNING:

During road tests, vehicle, test equipment must always be fastened to and operated from the rear seat by a second technician.
Observe safety precautions. See SAFETY PRECAUTIONS .