Description & Operation
WARNING: This page is about a different car, the 2003 Toyota Prius and 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
For warnings and procedures regarding vehicles equipped with Anti-Lock Brake Systems (ABS), see appropriate ANTI-LOCK article.
WARNING:
On Prius, read service precautions before proceeding with any service procedure. See SERVICE PRECAUTIONS .
Hydraulic Brake Booster (HBB) System consists of brake fluid reservoir, pressure accumulator, hydraulic pump motor, brake master cylinder and associated electrical components. System is connected to Anti-Lock Brake (ABS) system ECU to allow for ease of fault diagnosis and isolation.
Operation of brake pedal applies hydraulic pressure to front brakes assisted by brake booster and accumulator pressure. Rear brakes receive hydraulic pressure from accumulator directly. In the event of HBB pump motor failure, brake pressure to rear wheels will be lost. Brake system warning buzzer sounds in event of system pressure failure, or excessive pump motor operation.