The system operates only when the driver is in the vehicle or within operational range while the key is being carried.
Starting the Engine
NOTE
If the vehicle is started and the key is not in the vehicle, the vehicle will not restart after it is shut off and the ignition is switched to off.
With the advanced keyless function

Without the advanced keyless function

NOTE
The engine may not start if the key is placed in the following areas:
Transmitter
Key Suspend FunctionMazda 6 Owners Manual: Turning the Engine Off
WARNINGDo not stop the engine while the vehicle is moving: Stopping the
engine while the vehicle is moving for any reason other than in an emergency is
dangerous. Stopping the engine while the vehicle is moving will result in reduced
braking ability due to the loss of power braking, which coul ...
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
...