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: Glass panel adjustment
1. Fully close the glass panel.
2. Measure the gap and height between the glass panel and body.
3. If not as specified, loosen the glass panel installation screws and
reposition the glass panel.
Clearance
a: -0.8-1.2 mm {-0.032-0.047 in}
b: 0 mm {0 in}
4. Tighten the installation scre ...
Mazda 6 Owners Manual: Bonnet adjustment
Gap Adjustment
1. Remove the front fender.
2. Loosen the bonnet hinge installation bolts and reposition the bonnet.
3. Tighten the bolts.
4. Verify that the gap between the bonnet and the body is within the
specification.
Clearance
a: 2.5-4.5 mm {0.08-0.17 in}
Height Adjustment
1 ...