Inspect the PCM. (See PCM INSPECTION.)
Mazda 6 Service Manual: Starting a Flooded Engine
If the engine fails to start, it may be flooded (excessive fuel in the engine).
Follow this procedure:
1. If the engine does not start within five seconds on the first try, wait ten
seconds and try again.
2. Make sure the parking brake is on.
3. Depress the accelerator all the way and hold it ...
Mazda 6 Service 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
...