Which component will activate the master cylinder in the event of a vacuum pump failure on a hybrid? A) The brake pedal push rod B) The active brake booster C) The Brake Pedal Position (BPP) switch D) The ABS module

## Step 1<br />The problem is about the operation of a hybrid vehicle's braking system, specifically the activation of the master cylinder in the event of a vacuum pump failure. The vacuum pump is a crucial component in the braking system of a hybrid vehicle. It helps to reduce the effort needed to apply the brakes by creating a vacuum that assists the brake booster.<br /><br />## Step 2<br />Option A, "The brake pedal push rod," is a mechanical component that transmits the force of the driver's foot on the brake pedal to the brake system. However, it does not directly activate the master cylinder.<br /><br />## Step 3<br />Option B, "The active brake booster," works in conjunction with the vacuum pump to assist in braking. However, it is not the component that directly activates the master cylinder in the event of a vacuum pump failure.<br /><br />## Step 4<br />Option C, "The Brake Pedal Position (BPP) switch," is a sensor that detects the position of the brake pedal. In the event of a vacuum pump failure, the BPP switch can activate the master cylinder directly, ensuring that the brakes function even without the assistance of the vacuum pump.<br /><br />## Step 5<br />Option D, "The ABS module," is responsible for modulating brake pressure in emergency braking situations to prevent the wheels from locking up. While it plays a crucial role in the braking system, it does not directly activate the master cylinder in the event of a vacuum pump failure.