One problem related to brake light on has been reported for the 2002 Toyota Prius. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2002 Toyota Prius based on all problems reported for the 2002 Prius.
Brake and abs light came on. Brakes lost complete braking ability. Luckily we were on a hill off the interstate exit when this happened so the car could not go further, though it almost crashed into the person in front of us (that person turned off road). This is 100% dangerous! the car currently sits at my house. Too dangerous to drive. When brake pads were checked last I was told brakes were 80% new, so it is clearly not the pads.