The driver side airbag did not deploy in a front end collision on the drivers side. When approaching a vehicle that had come to a sudden and complete stop, the brakes were applied hard to the Mazda CX-9 in order to stop, but after about 1 second they just totally let go and there was no braking at all and the Mazda continued to move forward until it slammed into the vehicle that was stopped. The MyMazda app sent a message that stated that there was a Brake System Malfunctiom which is exactly what occurred and caused the accident.