If your vehicle rapidly closes in on the vehicle ahead because the vehicle applies the brakes suddenly while you are traveling in headway control, the warning sound activates and the brake warning is indicated in the display. Always verify the safety of the surrounding area and depress the brake pedal while keeping a safer distance from the vehicle ahead.
Additionally, always keep a safer distance from the vehicles behind you.

Mazda Radar Cruise Control (MRCC) Display Indication
Setting the SystemMazda 6 Owners Manual: Transmitter battery replacement
1. Insert a small screwdriver into the slot and gently pry open the
transmitter.
2. Press the portion of the battery indicated by A and remove the battery.
3. Install a new battery (CR2025) into the front portion of the holder with
the positive pole (+) facing up. Press on the B portion of ...
Mazda 6 Owners Manual: Floor Mat
We recommend the use of Genuine Mazda floor mats.
WARNING
Make sure the floor mats are hooked on the retention pins to prevent them
from bunching up under the foot pedals: Using a floor mat that is not secured
is dangerous as it will interfere with the accelerator and brake pedal operation,
...