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: Forward Sensing Camera (FSC) (Some models)
Your vehicle is equipped with a Forward Sensing Camera (FSC). The Forward Sensing
Camera (FSC) is positioned near the rearview mirror and used by the following systems.
High Beam Control System (HBC)
Lane-keep Assist System (LAS) & Lane Departure Warning System (LDWS)
Traffic Sign Reco ...
Mazda 6 Owners Manual: Magnetic clutch adjustment
1. Measure the clearance around the entire circumference between the pressure
plate and A/C compressor pulley using a thickness gauge.
2. Verify that the clearance is within the specification.
If not within the specification, remove the pressure plate and adjust
the clearance by changing ...