When starting my 2006 Audi A8 L The service message comes on. What does this mean

If you mean WHILE starting, cranking over, it's supposed to come on, all warning lights will. If it goes out when it starts (your '06 Audi should not take long, should fire right up by the way) then it means nothing

can mean MANY things, previous Audi owner, and mechanic (Love that model), the "L" actually was designed as a Long, and specifically for Asia, where in their culture the royalty/important people sit only in the back. And they by demand requested longer wheel bases!!!!!!!anyway, it is only during starting and goes away? but can be a reminder for maintenance, can you post a picture to show?