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: Rear door trim removal/installation
1. Disconnect the negative battery cable if equipped with power window
system.
2. Remove the regulator handle if equipped.
3. Open the cap using a small screwdriver, then remove the screw.
4. Remove the inner handle cover.
5. Remove the cover, then remove screw.
6. Disengage clips A from th ...
Mazda 6 Owners Manual: Power window main switch inspection
Drivers side
1. Remove the driver-side front door trim.
2. Connect the power window main switch connector.
3. Measure the voltage at the power window main switch terminals as indicated
below.
4. Disconnect the power window main switch connector before inspecting for
continuity at terminals 1 ...