I also had this same problem on my a4 67 plate 32 k my driveway is steep after stopping the car rolled back about 3 inches while i was applying handbrake warning came up . After driving it the next morning warning was still there i drove 20 miles to wirk and back and it had resolved itself hope this helps
Brake servo restricted
in Audi A4 (B9) Forum
Posted
I also had this same problem on my a4 67 plate 32 k my driveway is steep after stopping the car rolled back about 3 inches while i was applying handbrake warning came up . After driving it the next morning warning was still there i drove 20 miles to wirk and back and it had resolved itself hope this helps