A circle with a slash through it is a safety symbol which means "Do Not," "Do not do this," or "Do not let this happen."
A box with the word CAUTION is used to tell about things that could hurt you or others if you were to ignore the warning.
Caution: These mean there is something that could hurt you or other people.
Cautions tell what the hazard is and what to do to avoid or reduce the hazard. Read these cautions.
A notice tells about something that can damage the vehicle.
Notice: These mean there is something that could damage your vehicle.
Many times, this damage would not be covered by the vehicle's warranty, and it could be costly. The notice tells what to do to help avoid the damage.
There are also warning labels on the vehicle which use the same words, CAUTION or Notice.