Inspect your pads and make sure you have some material left. If they are worn down pretty good (especially the front), chances are that you are low on brake fluid. The sensor in the reservoir is pretty sensitive when you have low fluid. Simply remove the cap and push that rubber thing back up into it. If you don't do this you will push the fluid out of the reservoir. I had the same problem on my car a couple of months ago - turned out I needed front pads. I fixed the light temporarily by adding fluid. Just remember that if it is your pads and you add fluid, you will have to remove some fluid when you put new pads on. Sorry for the long post!! Good Luck!