1. Remove the rear door unit.
2. Remove the screws, then remove the rear door latch and lock actuator.

3. Install in the reverse order of removal.
Front door latch and lock actuator removal/installation
Front door key cylinder removal/installationMazda 6 Service Manual: Immobilizer System
The immobilizer system allows the engine to start only with a key the system
recognizes.
If someone attempts to start the engine with an unrecognized key, the engine
will not start, thereby helping to prevent vehicle theft.
If you have a problem with the immobilizer system or the key, consult ...
Mazda 6 Service Manual: Rear View Monitor Operation
The operation of the rear view monitor when reversing the vehicle varies depending
on the traffic, road, and vehicle conditions. The amount of steering and the timing
also varies depending on conditions, so confirm the surrounding conditions directly
with your eyes and steer the vehicle in acc ...