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: Scheduled Maintenance (Mexico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following
conditions apply.
Repeated short-distance driving
Driving in dusty conditions
Driving with extended use of brakes
Driving in areas where salt or other corrosive materials are used
Driving on rough or muddy ...
Mazda 6 Owners Manual: Variable intake-air system (vis) shutter valve actuator inspection (l3)
1. Remove the air hose. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
2. Disconnect the vacuum hose from the VIS shutter valve actuator.
3. Connect a vacuum pump to the VIS shutter valve actuator.
4. Apply vacuum and verify that the rod moves.
If the rod dose not move, replace the intake ma ...