The TT comes with an interesting array of warning lights and icons. Some are displayed on the gauge faces themselves whereas others are on the little LCD. Here's a rundown of some possibly unfamiliar lights you may encounter:
Gauge face lights:
Airbag - likes to come on and stay on when you unplug components of the airbag system (such as the seats). AFAIK, only a dealer can reset it.
Check Engine Light (CEL) - get used to it. It could be anything.
A hazard triangle with a circle around it - this is traction control. It blinks when you lose grip, it stays on when you turn traction control off.
EPC - Electronic power control. This light comes on when there's something amiss with your engine that makes the ECU feel the need to cut power. For example, if you overboost or misfire, the EPC light may come on.
A key and a car - this indicates an immobilizer issue.
BRAKE - your E-brake is on.
Icons in the center display
A lightbulb - means you have a burnt out bulb somewhere.
Something that looks ilke an erupting volcano - you're low on washer fluid.
(O) - your brake pads are worn.
There's more. These are just the not-so-obvious ones I know of.