The hazard warning lights should always be used when you stop on or near a roadway in an emergency.

The hazard warning lights warn other drivers that your vehicle is a traffic hazard and that they must take extreme caution when near it.

Depress the hazard warning flasher and all the turn signals will flash. The hazard warning indicator lights in the instrument cluster flash simultaneously.
NOTE
Horn
HomeLink Wireless Control System (Some models)Mazda 6 Owners Manual: Locking, Unlocking the Doors
NOTE
The system may not operate if you are too close to the windows or door
handles.
If the key is left in the following areas and you leave the vehicle,
the doors may be locked depending on the radio wave conditions even if the key
is left in the vehicle.
Around the dashboard
...
Mazda 6 Owners Manual: Dtc table
Note
Perform the following if the security light stays on:
- If gasoline engine stalls, go to symptom troubleshooting NO.11
ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK,
HESITATION/STUMBLE, SURGES in. (See NO.11 ENGINE STALLS/QUITS, ENGINE RUNS
ROUGH, MISSES, BUCK/J ...