According to the National Highway Traffic Safety Administration (NHTSA), more than 1-million 2006-2012 Ford Fusion, Lincoln MKZ and 2006-2011 Mercury Milan vehicles are now included in an investigation into soft brake pedals.
NHTSA opened the original investigation in December 2016, according to carcomplaints.com, based on soft brake pedals reported on 2007-2009 Ford Fusion and Mercury Milan vehicles. Owners reported that after the anti-lock braking systems activated, the brake pedal went low or to the floor and drivers experienced unexpectedly long stopping distances.
One vehicle owner said that his 2012 Ford Fusion hybrid completely failed to stop while his son was driving. He reported that the vehicle was going 30 mph at the time and his son used the parking brake to stop the car. The car was towed Ford dealer where a failed ABS module was later diagnosed.
The problem apparently stems from a valve inside the ABS module that may become corroded and stick during or after ABS activation. Some videos found online explain the issue in further detail:
The anti-lock braking system hydraulic control units found on these vehicles are manufactured by Continental Automotive Systems. NHTSA says the hydraulic control valves can become corroded and stuck, causing soft brake pedals and longer stopping distances. Some owners have reported that the problem is intermittent because the brakes sometimes go back to normal when the valves subsequently become unstuck. This is makes diagnosis a challenge.