NHTSA Complaint #11584171 — 2021 GMC SIERRA 3500

When starting the vehicle, I got a message to service the parking brake (this is the second time I’ve had this warning appear in the 21,000 miles I’ve owned it, first was approximately 5,000 miles ago). When this warning is active the parking brake does not engage, and can’t be used to stop the vehicle when the brakes fail as they did today. With 42,774 miles on the vehicle, and the onboard monitor for brake wear showing remaining brake life at 94% front and 96% rear, brake fluid reservoir between Max and Min the brake pedal went soft and the vehicle would not stop. I resorted to putting the vehicle in neutral and pumping the brakes until the pedal got hard. As soon as I let off the brake my vehicle began to roll backwards, stepped on the brake pedal again and the pedal again went to the floor without stopping or slowing the vehicle (pumping the brakes got it stopped again inches away from running into my house). The myGMC app notified me that I need to service the ABS system. I had the vehicle towed to the dealership for diagnostics and repair. Possibly related, this afternoon before the brakes stopped working I felt a mild vibration when traveling 20-35mph that resembled the vibration that occurs when a wheel bearing has begun to fail. Tow truck driver witnessed the vehicles inability to stop when putting it in neutral to load vehicle. It is unimaginable that a vehicle can be placed on the highway that has no backup system in the event of brake failure. Had a kid run out in front of me there would have been no way to avoid the accident (no other warnings appeared to indicate the vehicle was unsafe to drive. Brakes worked correctly and stopped appropriately until they didn’t).