To remove the fuel-filler cap, turn it counterclockwise.
Attach the removed cap to the inner side of the fuel lid.
To close the fuel-filler cap, turn it clockwise until a click is heard.

CAUTION
(U.S.A. and Canada)
If the check fuel cap warning light illuminates, the fuel-filler cap may not be properly installed. If the warning light illuminates, park your vehicle safely off the right-of-way, remove the fuel-filler cap and reinstall it correctly.
After the cap has been correctly installed, the fuel cap warning light may continue to illuminate until a number of driving cycles have been completed. A drive cycle consists of starting the engine (after four or more hours with the engine off) and driving the vehicle on city and highway roads.
Continuing to drive with the check fuel cap warning light illuminated could cause the check engine light to illuminate as well.
Fuel-Filler Lid
Steering WheelMazda 6 Owners Manual: Engine removal/installation
Warning
Fuel vapor is hazardous. It can very easily ignite, causing
serious injury and damage. Always keep sparks and flames away from fuel.
Fuel line spills and leakage are dangerous. Fuel can ignite and
cause serious injures or death and damage. Fuel can also irritate skin and
eyes. ...
Mazda 6 Owners Manual: Selector lever disassembly/assembly
1. Disassemble in the order shown in the figure.
2. Assemble in the reverse order of disassembly.
Connector Disassembly Note
1. Insert a thin piece of metal from the terminal side of the connector, and
press down the terminal locking tab.
2. Pull the terminal out of the connector. ...