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: Front crossmember removal/installation
1. Remove the under cover.
2. Remove the splash shield.
3. Remove the front auto leveling sensor. (See FRONT AUTO LEVELING SENSOR
REMOVAL/INSTALLATION.)
4. Remove the transverse member. (See TRANSVERSE MEMBER
REMOVAL/INSTALLATION.)
5. Remove the steering gear and linkage, and pipe assembly i ...
Mazda 6 Owners Manual: Driving In Flooded Area
WARNING
Dry off brakes that have become wet by driving slowly, releasing the accelerator
pedal and lightly applying the brakes several times until the brake performance
returns to normal: Driving with wet brakes is dangerous. Increased stopping
distance or the vehicle pulling to one side when ...