Turn the auxiliary key toward the front to lock, toward the back to unlock.
To lock
All doors lock automatically when the driver's door is locked using the auxiliary key.
To unlock
The driver’s door unlocks when the auxiliary key is turned briefly to the unlock position and then immediately returned to the center position.
All doors unlock when the driver's door is unlocked and the auxiliary key is held in the unlock position for one second or longer.

Door Locks
Locking, Unlocking with Request Switch, Door Handle (With the advanced keyless
function)Mazda 6 Owners Manual: Closing the Hood
1. Check under the hood area to make certain all filler caps are in place and
all loose items (e.g. tools, oil containers, etc.) have been removed.
2. Lift the hood, grasp the padded area on the support rod, and secure the support
rod in the clip. Verify that the support rod is secured in the c ...
Mazda 6 Owners Manual: Saving Fuel and Protection of the Environment
How you operate your Mazda determines how far it will travel on a tank of fuel.
Use these suggestions to help save fuel and reduce CO2.
Avoid long warm-ups. Once the engine runs smoothly, begin driving.
Avoid fast starts.
Drive at lower speeds.
Anticipate when to apply the brakes (avoid ...