Engine Management Light has come on

[A8 Owner]

Hi all today started car and this engine light came on. I rang steve to ask him what it ment, he said check manual. Manual dont say much than take it to dealer. Can anyone here help. Is it safe to drive, anything to look for. Seems to be running fine, so its just had full service last week.
So im asking is it safe to drive?
If there is somthing that could cause this to come on, what?
Then at least i can ask garage to check the poss causes out.

Thanks Mel