When doing an Adblue / SCR / Urea / DEF delete on a Mercedes Benz 350 CDI model this Plug needs to be disconnected.
It is also important to unplug the Nox sensor on the undertray of the Car. See attached Pictures for Info.
Remove this Plastic cover from the underside of the Car.
You then see this Plug.
Unplug it like shown in the Picture. Don't forget to put the Plactic cover back on.
