Hi All, I've joined the forum to let others know some information that I found useful, and I believe some might find this useful.
I have a 2017 Audi A4 B9 2.0 TDI with one year used approved warranty.
I had the dreaded Brake Servo Restricted message come up and my Start/ Stop disabled message.
I had to get to destination, tested the brakes and they worked, however when pressing on the brakes, it was clunking and crunching when braking which wasn't smooth.
Whilst driving, I found that the brakes were ok, and no issues except when slowing down then the clunking and crunching began.
I then got to the place I needed to be around 15 miles later.
I called out the Audi Assist team and they seemed to already know the issue. The Mechanic/ engineer plugged in the diagnostics to my OBD and said did the problem happen at this time. I said yes. He told me I did the right thing to call straight away.
He said if you do not follow the warning take to workshop and you continue driving, after around 300 brake press on the pedal the car's ABS will start feeding in pressure, and cause loads of ABS Module problems and that repair will not be covered under warranty, this is because the driver continued driving the vehicle with the warning light on.
The part replaced was the Brake Boost Pressure, and it was covered under Warranty, thank fully.