1. Remove the front door trim.
2. Using a flathead screwdriver, press and hold the hook in the direction indicated by arrow (1), and pull the shaft in the direction indicated by arrow (2), remove the shaft.

3. Pull off the inner handle, and remove the door lock knob cable and inner handle cable.
4. Install in the reverse order of removal.
Rear outer handle removal/installation
Regulator handle removalMazda 6 Service Manual: Oil leakage inspection
Use either of the following procedures to identify the type of oil that
is leaking:
Using UV Light (Black Light)
1. Remove on the engine or transaxle.
Note
Referring to the fluorescent dye instruction manual, mix the
specified amount of dye into the engine oil or ATF (or transaxle ...
Mazda 6 Service Manual: Dsc on-board diagnosis
On-Board Diagnostic (OBD) Test Description
(See ABS (ABS/TCS) ON-BOARD DIAGNOSIS)
DTC Table
PID/DATA Monitor Table
Active Command Modes Table
...