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 AdjusterRefrigerant Pressure Sensor Inspection [Manual Air Conditioner]
MZR 2.0, MZR 2.5
1. Install the manifold gauge.
2. Verify the high-pressure side reading of the manifold gauge.
3. Measure the terminal voltage of the climate control unit.
1G,1H and 2J
4. Verify that below graph as measure the terminal voltage 2J.
5. Follow the climate control ...
PCM Configuration [Mzr 2.0, Mzr 2.5]
CAUTION:
If the wheel and tire sizes are changed, a discrepancy with the speedometer
needle whereby it exceeds the allowable range could result in a malfunction.
If the wheel and tire sizes are changed, perform the following procedure to
change the tire size parameter setting..
...
Theft Deterrent System Reading Freeze Frame Data
1. Connect the M-MDS (IDS) to the DLC–2.
2. After the vehicle is identified, select the following items from the initialization
screen of the IDS.
Select “Body”.
Select "Burglar Service Functions".
3. Then, select the following item from the screen menu. ...