Take the appropriate action and verify that the warning light turns off.

Taking Action
Message Indicated on DisplayMazda 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: Front door speaker inspection
1. Inspect for resistance between the front door speaker terminals using an
ohmmeter.
If not as specified, replace the front door speaker.
2. To verify that the front door speaker outputs sound, apply voltage to the
front door speaker and release using a 1.5-V battery.
If not outp ...