Active brake booster (hybrid vehicles)

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The active brake booster uses vacuum supplied by an electric vacuum pump mounted on the engine when engine vacuum is unavailable. The active brake booster is similar to a conventional brake booster but with the addition of a brake booster (vacuum) solenoid, a brake booster travel sensor and a vacuum sensor. If it is necessary to apply the friction brakes, the ABS module will send a Pulse Width Modulated (PWM) signal to the brake booster solenoid that is proportional to the amount of brake torque requested. The booster solenoid will open to allow vacuum to draw the booster diaphragm and push rod toward the master cylinder piston, building hydraulic pressure. The vacuum sensor is used by the ABS module to monitor vacuum maintained inside the brake booster. The brake booster travel sensor is used to monitor the performance of the brake booster.