Pinpoint Tests AH: Brake Booster Vacuum Supply Faults: Notes
WARNING: This page is about a different car, the 2019 Ford F-550 Super Duty, 2019 Ford F-450 Super Duty, 2019 Ford F-350 Super Duty, and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
On all other engines, the engine supplies the vacuum to the brake booster through a series of hoses and tubes. A leak in a vacuum hose, tube, brake booster or one of the seals on the brake booster or vacuum pump prevents the brake booster from achieving the required amount of vacuum.