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: Foot Brake
This vehicle has power-assisted brakes that adjust automatically through normal
use.
Should power-assist fail, you can stop by applying greater force than normal
to the brake pedal. But the distance required to stop will be greater than usual.
WARNING
Do not coast with the engine stalled or t ...
Mazda 6 Service Manual: Parking brake (lever type) adjustment
1. Start the engine and depress the brake pedal several times.
2. Stop the engine.
3. Remove the ashtray behind the center console.
4. Turn the adjusting nut as shown in the figure.
5. After adjustment, inspect the following points:
(1) Turn the ignition switch to ON, pull the parking brak ...