Displays in the following cases:

Stop Vehicle in Safe Place Immediately
Message Indicated in Multi-information DisplayMazda 6 Owners Manual: Immobilizer system reprogram procedure
Note
When an error occurs during the reprogram procedures, except when
the PCM is replaced, repeat the procedure from Step 1. If you still cannot
reprogram, confirm how many keys can start the engine. Then, perform the key
replacement or addition reprogram procedure according to the val ...
Mazda 6 Owners Manual: Front door speaker removal/installation
1. Disconnect the negative battery cable.
2. Remove the front door trim.
3. Remove in the order indicated in the table.
4. Install in the reverse order of removal.
Front Door Speaker Installation Note
Attach the speaker with the wiring harness placed in the groove of the door
unit panel.
...