One problem related to brake sensor has been reported for the 2004 Toyota Prius. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota Prius based on all problems reported for the 2004 Prius.
We own a 2004 Toyota Prius and have been very pleased with it until it recently experienced a sudden brake failure. After stopping at a rest stop and preparing to return to the interstate, my wife experienced a complete brake failure as she drove the vehicle in reverse from the parking area. She then drove the vehicle forward to get it out of the traffic lane and continued to not have brakes. The vehicle was towed to amarillo, TX where the Toyota dealer repaired the vehicle by replacing the stroke sensor (scanned system code c1247).