It means that there are certain maintenance items that needs to
be done at this time. Each time the odometer reaches a set factory
mileage, it trips this light notifying you that something needs to
be done. Look in your owners manual to see exactly what maintenance
you should perform.
ANSWER I have a 2000 Grand Cherokee
and wondered the same thing. In my vehicle, it is a user set
function. You can set it to go off at various intervals to remind
you that something is due. I have it set for 3,000 miles to remind
me that the oil change is due. It can also be reset by me. As the
last poster stated, see your user's manual.