I was on the highway traveling at 60mph, with the adaptive cruise control on. The semi in front of me began to brake, I tapped off the cruise control and began braking. The semi came to a complete stop and I pushed my brake pedal to the floor to stop my vehicle. It did not stop. My Pinnacle has emergency braking and forward collision warning. My driver's instrument panel did not give a forward collision warning indication in a timely manner and my emergency braking did not stop my vehicle. At the time of the accident vehicle had less than 10,000 miles, dry weather conditions, and vehicle was used for leisure - in town driving. A month previously, I took my Pinnacle into the dealership because I didn't feel my brakes were working properly. They felt mushy, little resistance, and were making a noise. An inspection was performed by the dealership but were unable to detect a noise or visual issue. My safety was put at risk when a system I depended upon, that was advertised as, "Full speed forward collision warning with active braking assists you by providing both visual and audible warnings as well as applying emergency braking to help bring the vehicle to a full stop, if needed" (chrysler.com/pacifica/safey-security.html) failed. The brakes didn't engage properly to stop us before hitting the vehicle in front of us. The forward collision warning indication didn't happen in a timely manner, it was delayed causing us to lose precious seconds. If this had been a passen