What does this mean ( ! ) when it is lit up on the dash?

Actually what that indicator means is that someone in the car used incorrect grammar while conversing. I once substituted 'conversating' for 'having a conversation' and the ! flashed 3 times then stayed on. Two minutes later the PBS station was on the radio and I couldn't change it until I had an English professor speak the Kings English into the reset microphone under the dash by the glove compartment. Just kidding of course, Tom is right. But there is also another amazing feature that cars come with. It's called "The least read book in the world." Also called the owners manual. It's a great read!

Hi! Does anybody know what a sign 'A' in the temperature measurement place of my Nissan Centra 2009 car means? Thank you!

Tire pressure is low