Take the appropriate action and verify that the warning light turns off.

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Woofer inspection
1. Inspect for continuity between the audio amplifier connector terminals and
woofer connector terminals using an ohmmeter.
If not as specified, replace the related wiring harnesses.
2. Verify that there is battery positive voltage at the woofer connector
terminal A (4SD) or C (5HB) u ...
Mazda 6 Owners Manual: Fuel-Filler Cap
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 ...