It's a mistake. You mean VW 501.01.
VW 504/507 may be used in engines calling for VW 505.01, but with a few exceptions: 3, 4, and 5 cylinder PD engines with or without DPF, that are not equipped for "Long Life Service," require still VW 505.01.
VW 91101 is an automobile environmental standard pertaining to materials used in car manufacturing and maintenance. It is, for example, applicable to automobile carpeting, wiring, dashboard plastic. VW 91101 is similar to Ford WSS-M99P999-A1, GMW3059, and Delphi A 10949001. These lists are about restricted and prohibited materials (think toxic content like dioxin and VOC).
I would expect all officially VW-approved oils, coolant, P/S fluid, etc to comply fully with VW 91101.
Didn't VW tell you guys tell this when you contacted them? You did try getting an answer straight from the horse's mouth, right?
We did contact the manufacturing plant. Only for the purpose of knowing what oil is put in from the factory. They sent a 15 page service bullitin with test data and analysis. There is a lot of data there but unless you are a rocket scientist it might as well be a foriegn lang. The summary states that changes have been made as compared to Technical Supply Specification TL 521 67. Then as follows: VW standard VW91101. This TL's title is Factory-Fill Engine Oil SAE 5w-40 Lubricant requirements. The scope on the TL states that the factory fill oil id suitable for service interval changes of 15,000
We are in the process of creating this list. I have one made up but this 911 thing has thrown a wrench in it because I can't find a single document other than the TL sent to us that explains what VW91101 is and what spec (501, 504, 505, 506, 507)covers it!