The manual shift mode gives you the feel of driving a manual transaxle vehicle by allowing you to operate the selector lever manually. This allows you to control engine rpm and torque to the drive wheels much like a manual transaxle when more control is desired.
To change to manual shift mode, shift the lever from D to M.

NOTE
Changing to manual shift mode while driving will not damage the transaxle.
To return to automatic shift mode, shift the lever from M to D.
NOTE
Active Adaptive Shift (AAS)
IndicatorsMazda 6 Owners Manual: Locking Lug Nuts
If your vehicle has Mazda optional antitheft wheel lug nuts, one on each wheel
will lock the tires and you must use a special key to unlock them. This key will
attach to the lug wrench.
Register them with the lock manufacturer by filling out the card provided in
the glove compartment and mail ...
Mazda 6 Owners Manual: Ignition switch inspection
1. Disconnect the negative battery cable.
2. Remove the column cover. (See COLUMN COVER REMOVAL/INSTALLATION)
3. Disconnect the ignition switch connectors.
4. Inspect for continuity between the ignition switch terminals using an
ohmmeter.
If not as specified, replace the ignition switch.
...