Why is my check engine light on

What is your question?

After sitting for a little over two months I started my Sprinter and it was slow to start up. When it finally started it ran rough for a few seconds then settle into the usual smooth purr. No check light at that time. Two days later I started it up and now the engine check light is on steadily and no codes or messages on the display between the tach and speedo. Popped the hood and crawled underneath, no signs of leaks of obvious problems. I'm close to a hundred miles from a shop and need to know what the steady check light means

How long has your 2019 Mercedes-Benz Sprinter 3500 had this problem?

2 days