FixVault

When Cooperative Regenerative Brake Control Is Operating

WARNING: This page is about a different car, the 2011 Nissan Leaf. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Motor And Piston Of Brake Booster (Cooperative Regenerative Brake Control Is Operating)
G07084552Courtesy of NISSAN MOTOR CO., U.S.A.

When the amount of regenerative braking increases, the motor inside the electrically-driven intelligent brake unit returns the master cylinder piston, lowering the fluid pressure. While the vehicle is stopped, because the amount of regenerative braking decreases, the motor inside the electrically-driven intelligent brake unit presses the master cylinder piston, increasing the fluid pressure.