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.
Mazda 6 Owners Manual: Troubleshooting procedure
Basic flow of troubleshooting
DTC troubleshooting flow (on-board diagnostic)
Diagnostic trouble codes (DTCs) are important hints for repairing
malfunctions that are difficult to simulate.
Perform the specific DTC diagnostic inspection to quickly and accurately
diagnose the malfunction.
The ...
Mazda 6 Owners Manual: Scheduled Maintenance (U.S.A., Canada, and Puerto Rico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following
conditions (severe driving conditions) apply.
Repeated short-distance driving
Driving in dusty conditions
Driving with extended use of brakes
Driving in areas where salt or other corrosive materials are used
...