Regenerative braking is a hybrid technology that enables the electric drive motor to operate as a generator when coasting or braking. Energy from the moving vehicle recharges the hybrid battery.
The hydraulic disc brakes work with the regenerative braking to insure effective braking, such as when a high braking demand is requested.
The braking system is computer controlled and blends the regenerative braking with the conventional hydraulic disc brakes to meet any requirements for deceleration. The controller interprets the braking request and uses regenerative braking, conventional hydraulic braking or a combination of both as necessary. Because the controller applies the hydraulic brakes through its high pressure accumulator, you may occasionally hear the motor driven pump when it recharges the system. This is normal.
See "Warning Lights, Gages, and Indicators" and "Driver Information Center (DIC)" in the Index of the owner manual. In the event of a controller problem, the brake pedal may be harder to push and the stopping distance may be longer.