Got my first fault code

[JakeLight]

For what it's worth I just when through this with both the P1985 and P1900:

18393 - Coolant Control Module 2 (J671)
P1985 - 002 - Malfunction

18308 - Coolant Fan Control 2
P1900 - 004 - Open or Short to Ground - Intermittent

My small aux fan was dead (drivers side US) - since Audi does not actually have any of these left I had to seek out an alternative. As far as I can tell the 300mm fan for any 2.7t A6 or Allroad of that era is part-identical, but to be specific I got the one made by Magneti Marelli and it both fits, and works perfectly - under $60 at partsgeek.

-jake

[AudiPilot]

For what it's worth I just when through this with both the P1985 and P1900:

18393 - Coolant Control Module 2 (J671)
P1985 - 002 - Malfunction

18308 - Coolant Fan Control 2
P1900 - 004 - Open or Short to Ground - Intermittent

My small aux fan was dead (drivers side US) - since Audi does not actually have any of these left I had to seek out an alternative. As far as I can tell the 300mm fan for any 2.7t A6 or Allroad of that era is part-identical, but to be specific I got the one made by Magneti Marelli and it both fits, and works perfectly - under $60 at partsgeek.

-jake

That's a huge help, knowing you went after the fan and not the control module... Given you had the exact same symptoms, I'll go that route!