Mazda CX-9 Owners Manual > When Driving: ABS/TCS/DSC/Trailer Stability
Control (TSC)
Antilock Brake System (ABS) The ABS control unit continuously monitors the speed of each wheel. If one wheel is about to lock up, the ABS responds by automatically releasing and reapplying that wheel's brake. The driver will feel a slight vibration in the brake pedal and may hear a chattering noise ...