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: Oil control valve (ocv) inspection
L3
Coil Resistance Inspection
1. Disconnect the negative battery cable.
2. Disconnect the oil control valve connector.
3. Measure the resistance between terminals A and B using an ohmmeter.
If not as specified, replace the oil control valve.
Specification
6.9-7.9 ohms
4. Connect ...
Mazda 6 Owners Manual: Dsc on-board diagnosis
On-Board Diagnostic (OBD) Test Description
(See ABS (ABS/TCS) ON-BOARD DIAGNOSIS)
DTC Table
PID/DATA Monitor Table
Active Command Modes Table
...