usually it means that something is wrong with it, but you'll probably have to look in the owner's manual
http://www.topix.com/forum/autos/chevrolet-impala/T4P2NGT979PJ7QT2P
Time to change your oil in your engine!
Add brake fluid
It requires a scanner to properly diagnosis a check engine light.
There is one screw that holds the fog light it into place.Unscrew that screw and the fog light will pull out of the bumper.
As per the instructions on page 5-55 of your "Owner's Manual"...
The most likely cause is the turn signal flasher.
It means your alternator (generator) is not charging the battery while the engine is running.
It is mounted on a bracket under the dash at the brake pedal. From there it is self explanatory.
You need to take it to a repair and have then scan the system for codes and diagnosis it. It could be as simple as dirt on a sensor.
The check engine light problem will have to be repaired in order to have someone with a scanner to reset it. If the repair is not made then the light will come back on immediately.
There is a sensor in the side of the oil pan. It will be defective.