Toyota Preliminary Evaluation PE10006: Braking Performance, Hybrid Vehicle

2010 Toyota Prius

Summary: The subject vehicles are the first model year of a new design generation of the Prius model line.The vehicles are powered by a hybrid drive system that uses both a regenerative braking system, which converts vehicle momentum into electrical energy to be stored in onboard batteries, and a hydraulic brake system more typical of the brake system used on non-hybrid vehicles.As is the case for other similarly designed hybrid vehicles the interaction and management of the two braking systems during ABS braking is complex and requires a sophisticated control system.In a February 9, 2010 Defect Information Report, Toyota advised the agency of its plans to conduct a safety recall to address inconsistent brake feel and increased stopping distances that may occur during braking events requiring ABS operation, such as would occur when braking on rough or low friction road surfaces.Toyota will reprogram the ABS control unit with improved software that addresses this condition.Based on Toyota's action the investigation is closed. ODI will continue to monitor the subject vehicles' performance and will take further action as future circumstances dictate.