Audi A7 2015 Error Code P204B

[Caesar]

Hi All

Just had the Engine Management light come on and had the car scanned by a friend. The Code that comes up is P204B.

Not sure what it is and what system sensor it refers to?

Any Help or Advice is greatly appreciated.

Caesar

 

[Belle427]

Seems to be pointing toward an ad blue system fault.
https://www.google.co.uk/search?q=audi+dtc+p204b&ie=UTF-8&oe=UTF-8&hl=en-gb&client=safari