Active Brake Booster

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The active brake booster is similar to a conventional vacuum assisted brake booster with the addition of a brake booster solenoid, a brake booster travel sensor, and a vacuum pressure sensor. If it is necessary to apply the friction brakes due to inadequate deceleration from regenerative braking, the ABS module will send a PWM voltage to the brake booster solenoid that is proportional to the amount of brake torque requested. The booster solenoid will open, which allows the vacuum booster push rod to push on the master cylinder creating pressure in the hydraulic system.

The ABS module uses the signals produced by the vacuum pressure sensor to verify that vacuum maintained in the brake booster. The ABS module uses the signals produced by the brake booster travel sensor to monitor brake booster performance. The brake booster travel sensor and the vacuum pressure sensor can be serviced separately from the brake booster.