I WAS DRIVING N/B 101. I PRESSED MY BRAKE TO AVOID A COLLISION CAUSING MY VEHICLE TO DECELERATE FROM 65 MPH TO 40 MPH. THIS RESULTED IN MY DAUGHTERS SEAT UN-LATCHING FROM THE FLOOR OF THE VEHICLE AND TILTING ALL THE WAY FORWARD, CAUSING MY 2 YEAR OLD DAUGHTER'S FACE TO BE SLAMMED INTO THE BACK OF THE PASSENGER SEAT. I PULLED OFF THE FREEWAY. I SAW THAT THE BACK LATCHES WERE IN THE POPPER PLACE ON THE FLOOR BUT WEREN'T LATCHING. I THEN TILTED THE SEAT UP AND PLACED IT DOWN HARD ABOUT 20 TIMES BUT IT STILL WOULD NOT LATCH. MY DAUGHTER WASN'T SERIOUSLY INJURED, SO AT THE PRESCHOOL ONE THE TEACHERS AND I READ THE MANUAL AND PULLED ON THE LATCH RELEASE SEVERAL TIMES AND TILTED THE SEAT FORWARD AND THEN BACK DOWN, BUT IT WOULD NOT LATCH. THEN ONE OF THE GRANDPARENTS OFFERED TO TRY AND HELP BUT STILL THE DEFECTIVE SEAT WOULDN'T WORK. I CALLED THE HONDA DEALERSHIP IN SAN JOSE CA ON STEVENS CREEK BLVD, WHERE I BOUGHT THE VEHICLE. THEY IMMEDIATELY SAID IT WAS THE MIDDLE SEAT AND THAT I MUST BE DOING SOMETHING WRONG BECAUSE THEY GET THE COMPLAINT ALL THE TIME. I DROVE TO THE DEALERSHIP AND ACCIDENTALLY STOPPED OFF AT THE VOLVO DEALERSHIP NEXT DOOR. THE VOLVO SERVICE GUY TRY TO SEE IF HER COULD FIX & AFTER NUMEROUS ATTEMPTS SAID THE SEAT WAS DEFECTIVE. I THEN IMMEDIATELY PROCEEDED TO THE HONDA DEALERSHIP. ONCE SERVICE PERSON TRIED TO LATCH THE SEAT, COULD NOT, AND THEN CALLED ANOTHER SERVICE GUY WHO INITIALLY COULD NOT GET THE SEAT TO LATCH. HE THEN PLACED A PEN AROUND THE LATCH