Depress the button on the seat belt buckle. If the belt does not fully retract, pull it out and check for kinks or twists. Then make sure it remains untwisted as it retracts.

NOTE
If a belt does not fully retract, inspect it for kinks and twists. If it is still not retracting properly, have it inspected at an Authorized Mazda Dealer.
Fastening the Seat Belt
Front Shoulder Belt AdjusterMazda 6 Owners Manual: General procedures
PRECAUTION (FRONT AND REAR AXLE)
Wheel and Tire Removal/Installation
1. The removal and installation procedures for the wheels and tires are not
mentioned in this section. When a wheel is removed, tighten it to 88-118 N·m
{9.0-12.0 kgf·m, 65.0-87.0 ft·lbf}
Brake Line Disconnection/Connecti ...
Mazda 6 Owners Manual: Auto Lock/Unlock Function
WARNING
Do not pull the inner handle on a front door: Pulling the inner handle
on a front door while the vehicle is moving is dangerous. Passengers can fall out
of the vehicle if the door opens accidentally , which could result in death or serious
injury.
When the vehicle speed exceeds 20 ...