See also:

If the light is blinking
If the light is blinking while driving, an engine misfire condition has been detected which may damage the emission control system. To prevent serious damage to the emission control system, y ...

Non-turbo models
...

Engine overheating
Never attempt to remove the radiator cap until the engine has been shut off and has fully cooled down. When the engine is hot, the coolant is under pressure. Removing the cap while the engine is ...