Always use the automatic locking mode to keep the child-restraint system from shifting to an unsafe position in the event of an accident. To enable seat belt automatic locking mode, pull it all the way out and connect it as instructed on the child-restraint system. It will retract down to the child-restraint system and stay locked on it. See the section on child restraint.
Emergency Locking Mode
Seat BeltMazda 6 Owners Manual: Solenoid valve removal/installation
1. Disconnect the negative battery cable.
2. Remove the under cover.
3. Remove the control valve body. (See CONTROL VALVE BODY REMOVAL.)
4. Remove the solenoid valve(s).
5. Apply ATF to a new O-ring and install it on the solenoid valve.
6. Install the solenoid valve in the control valve body. ...
Mazda 6 Owners Manual: Rocking the Vehicle
WARNING
Do not spin the wheels at more than 56 km/h (35 mph), and do not allow
anyone to stand behind a wheel when pushing the vehicle: When the vehicle
is stuck, spinning the wheels at high speed is dangerous. The spinning tire could
overheat and explode. This could cause serious injuries.
...