Through m.y. 2001:

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.

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 .