Where is the manual unlock code for the old A6 audio system?

[StMaggie]

The unlock code for the old Audi A6 audio system is located on the radio manual, specifically on a 4-digit password label in the lower right corner of the first page. The label also includes the disc player's serial number: AUZ5Z3D. Relevant information about the Audi A6 is as follows: The Audi A6 (C5) 2.4L is equipped with a longitudinally mounted 2.4L V6 engine, with a factory-rated maximum power output of 121KW and maximum torque of 230NM. The EA888 engine in the Audi A6 utilizes variable valve timing technology for the intake valves, effectively improving air intake and exhaust efficiency. This is primarily achieved through a vane-type hydraulic adjuster located on the intake camshaft. The vane-type adjuster consists of an outer housing, an internal vane rotor, and a locking pin inside the vane rotor. The outer housing is fixed to the external timing gear and driven by the crankshaft, while the internal vane is directly fixed to the intake camshaft and rotates with it.