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: Air bag module and pre-tensioner seat belt deployment procedures
Warning
A live (undeployed) air bag module and pre-tensioner seat belt may
accidentally deploy when it is disposed of and cause serious injury. Do not
dispose of a live (undeployed) air bag module and pre-tensioner seat belt.
If the SSTs (Deployment tool and Adapter harness) are not ava ...
Mazda 6 Owners Manual: Camera and Sensors
Forward Sensing Camera (FSC)
The Forward Sensing Camera (FSC) detects lane indications and recognizes headlights,
taillights and city lights during nighttime driving. In addition, it also detects
the vehicle ahead, pedestrians, or obstructions. The following systems also use
the Forward Sensi ...