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

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Front door key cylinder removal/installation
1. Remove the front door unit.
2. Remove the cover, then remove the bolt.
3. For protector-equipped vehicles, pull out the protector tab from the latch
and remove the protector.
4. Disconnect the rod.
5. Remove the front outer handle.
6. Turn the key cylinder in the direction indicated by ...
Mazda 6 Owners Manual: Warranties for Your Mazda
New Vehicle Limited Warranty
Powertrain Limited Warranty
Safety Restraint System Limited Warranty
Anti-perforation Limited Warranty
Federal Emission Control Warranty/California Emission Control Warranty
Emission Defect Warranty
Emission Performance Warranty
Emission Control Warranty ...