"ETK" is almost certainly a typo or shorthand for ETKA (German: Elektronischer Teilekatalog ). This is Volkswagen Group’s official electronic parts catalog system used by dealerships and repair shops.
Here’s what it likely refers to and why it’s notable: etk vw online
Would you like help finding a specific VW part number or understanding how to read an ETKA diagram? "ETK" is almost certainly a typo or shorthand
That is an interesting phrase: .