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, you sho ...

Washing the underbody
Chemicals, salts and gravel used for deicing road surfaces are extremely corrosive, accelerating the corrosion of underbody components, such as the exhaust system, fuel and brake lines, brake ...

ON
This is the normal operating position after the engine is started. ...