1. Connect the WDS or equivalent to the DLC-2.
2. Measure the PID value.
Note
PID/DATA MONITOR AND RECORD function table

Dtc p0841
TroubleshootingMazda 6 Service Manual: Illuminated Entry System
When the illuminated entry system operates, the overhead lights, the courtesy
lights, and an ambient light* turn on in the following conditions:
The driver's door is unlocked after the ignition is switched OFF.
The ignition is switched OFF with all doors closed.
NOTE
(Overhead lights) ...
Mazda 6 Service Manual: Cruise actuator removal/installation
1. Disconnect the negative battery cable.
2. Remove in the order indicated in the table.
3. Install in the reverse order of removal.
Cover Removal Note
Unclamp the clips of the heater hoses at the front of the cover.
...