Yellow Malfunction Indicator Lamp - how do I find what it is?

[Dave Wilson]

My yellow MIL (Malfunction Indicator Lamp) came on while driving. I stopped & locked the car, then re-started but it's still on. There's no loss of power and everything seems to be working ok. I expected to be able to see some kind of message on the dashboard but there's nothing to indicate what the light means - how do I find what it is?
(2015 A8L D4 W12)

 

[Darren92]

A diagnostic will tell you the direction to start looking.

 

[Dave Wilson]

Nothing I can do them? I have to take it to a dealer?

 

[Darren92]

It could be a million and one things.

Not necessarily a dealer visit required. A good specialist will be able to take it on.