Engine management light cannot measure fluid level

[Nathdonn]

EML came on 3 weeks ago. Took it for testing they did it and said lots worries and cleared the messages. 3 weeks later EML back on message saying only 500 miles until engine won’t start. AD blue error says can t measure fluid level? Any idea helpful ppl?

 

[OneForTheRoad]

Loads of info if you use the search feature.

But .

Problems are usually one of several things . Ad blue pump and crystals forming on the level sensors . Possibly nox sensors !!