My Adblue light came on just before Christmas, it jumped from 1500 miles to 750 miles to 384 miles within seconds.  I filled up but the light remained on and did not reset.  I put some specialist cleaner in the Adblue tank to clear any crystallisation that may have taken place. That did not resolve it.  It has  therefore gone to the garage.  They have called advising there is an Adblue update they need to put on the car, I am assuming that relates to the onboard computer.  

That  makes  no sense why the other would happen.  Anyone had a similar experience.  I am waiting for a call back to see if that resolves the issue but it doesn't sound right.  

Please let us know how you get on with it all