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: Air intake actuator inspection
1. Connect battery positive voltage to terminal D or F and ground to terminal
F or D of the air intake actuator.
2. Verify that the air intake actuator operates as shown below.
If not as specified, replace the air intake actuator.
...
Mazda 6 Owners Manual: Reassembly
Standard values, such as torques and certain adjustments, must be
strictly observed in the reassembly of all parts.
If removed, these parts should be replaced with new ones:
- Oil seals
- Gaskets
- O-rings
- Lockwashers
- Cotter pins
- Nylon nuts
Depen ...