Escape control module fault?

[Kwala]

My other half took her 2009 a3 1.8t in for a service at audi today.   On Saturday (great timing)  a warning message appeared that said "brake failure, drive to your nearest garage safely".    So this afternoon the garage called her up to say the "escape control module" is faulty and needs replaced.   £1000 they are quoting!  

Is this something I could fix myself with a secondhand part?  Where is the escape control module?  and what does it do? We were going to get her a newer car next September so would really like to get it through til then without giving Richard Turpin £1k!  

 

Any help or advice greatly appreciated!