Audi-04-DCW17-PV6

ZEXEL started manufacturing Swash-Plate compressor in 1967.
http://www.compressor-express.com/ac-compressor/audi/Audi-04-DCW17-PV6

Some Audi S6, Audi A6 and A8 are built with the same air conditioning compressor. The Original Equipment Manufacturer Numbers (OEM numbers) are Audi 4A0260805AB, 4A0260805AC, 4A0260805AD, 4A0260805AH, 4A0260805B, 4A0260805C, 4A0260805D, 8D0260805A.

The air-conditioning system of these vehicles was assembled with a Zexel DCW17 compressor. Manufacturer numbers: Zexel 506031-0831, 506231-0441.
These ac units seem to be interchangeable.

Audi-01-6SEU12C-PV6

DENSO is also the market leader in air conditioning compressors, with a 42% OE market share.

http://www.compressor-express.com/ac-compressor/audi/Audi-01-6SEU12C-PV6

Some Audi A4 are built with the same air conditioning compressor. The Original Equipment Manufacturer Numbers (OEM numbers) are Audi 8E0260805AF, 8E0260805G.

The air-conditioning system of these vehicles was assembled with a Denso 6SEU12C compressor. Manufacturer numbers: Denso 447150-0560, 447170-7920, 447170-7921, 447170-7923, 447170-7924, 447180-6700, 447190-8050.

These ac units seem to be interchangeable.