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: Instrument cluster configuration
1. Connect the SST (WDS or equivalent) to the DLC-2.
2. Input vehicle information following the directions on the screen.
3. Select Module programming.
4. Select Programmable module installation.
5. Select the following items and perform procedures according to directions
on the screen.
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Mazda 6 Owners Manual: Crash zone sensor removal/installation
Warning
Handling the crash zone sensor improperly can accidentally deploy the air bag
module and pre-tensioner seat belt, which may seriously injure you. Read AIR BAG
SYSTEM SERVICE WARNINGS before handling the crash zone sensor. (See SERVICE
WARNINGS.)
1. Turn the ignition switch to LO ...