philipellis

Hi

I had a message come up yesterday saying that I was low on Adblue but when I went into the Service menu it showed that I'd got half a tank left.
I thought maybe it was a blip, so I topped it up anyway with 3.5 litres. Today, it is showing as full but with only 1000 miles of range and a red line at the 1/2 marker.

Does anyone know what this could be?

Thanks.