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: General procedures
PRECAUTION (FRONT AND REAR AXLE)
Wheel and Tire Removal/Installation
1. The removal and installation procedures for the wheels and tires are not
mentioned in this section. When a wheel is removed, tighten it to 88-118 N·m
{9.0-12.0 kgf·m, 65.0-87.0 ft·lbf}
Brake Line Disconnection/Connecti ...
Mazda 6 Owners Manual: Transmitter battery inspection
Caution
Since the battery voltage does not drop fully if the button is
pushed for only 4 seconds or less, it can not be properly examined to see
whether it is good or bad. Always push the button for 5 seconds.
Note
A correct measurement can not be obtained if the battery
temperat ...