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

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Expansion valve removal/installation
1. Disconnect the negative battery cable.
2. Discharge the refrigerant from the system. (See RECOVERY.) (See CHARGING.)
Caution
If moisture or foreign material enters the refrigeration cycle,
cooling ability will be lowered and abnormal noise will occur. Always
immediately plug open fitt ...
Mazda 6 Owners Manual: Trunk Lid
WARNING
Never allow a person to ride in the trunk: Allowing a person to ride
in the trunk is dangerous. The person in the trunk could be seriously injured or
killed during sudden braking or a collision.
Do not drive with the trunk lid open: Exhaust gas in the cabin of a vehicle
is dangerous. ...