Hi,
Had same issue on 2016 Audi A4 - “Brake Servo Restricted and Start/Stop System Fault” came on when starting the car but no lights on dash. Contacted Audi Garage and was strongly instructed not to drive the car any further due to possible damage of ABS pump which was quoted at €2500 to fix. Despite the fault indicated to continue to drive but contact dealer.
From this forum, I ordered the Brake pressure sensor (€99) and followed the you tube video provided and the problem is now solved.
Very grateful for all the information provided on this site. Was quoted €340 and €180 from 2 different Audi garages. I changed the sensor in less than 2 minutes and I have no previous mechanic background at all!
