All doors lock automatically when the lock side is pressed. They unlock when the unlock side is pressed.
Driver's door

Front passenger's door

To lock all the doors from an open front door, press the lock side of the door lock switch and then close the door.
NOTE
When locking the doors this way, be careful not to leave the key inside the vehicle.
Locking, Unlocking with Transmitter
Auto Lock/Unlock FunctionMazda 6 Owners Manual: Front fender panel
FRONT FENDER PANEL REMOVAL/INSTALLATION
1. Disconnect the negative battery cable.
2. Remove the front side turn light.
3. Remove the fender molding. (See COWL GRILLE REMOVAL/INSTALLATION.)
4. Remove the front bumper. (See FRONT BUMPER REMOVAL/INSTALLATION.)
5. Remove the front combination light ...
Mazda 6 Owners Manual: Foreword
When the customer reports a vehicle malfunction, check the malfunction
indicator lamp (MIL) indication and diagnostic trouble code (DTC), then
diagnose the malfunction according to following flowchart.
- If a DTC exists, diagnose the applicable DTC inspection. (See DTC
TABLE.)
- ...