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: Speedometer, Odometer, Trip Meter and Trip Meter Selector (Without Multiinformation
Display)
The speedometer indicates the speed of the vehicle.
The display mode can be changed from odometer to trip meter A to trip meter B
and then back to odometer by pressing the selector while one of them is displayed.
The selected mode will be displayed.
Odometer
The odometer records the total d ...
Mazda 6 Service Manual: Installation of radio system
If a radio system is installed improperly or if a high-powered type is used,
the CIS and other systems may be affected. When the vehicle is to be equipped
with a radio, observe the following precautions:
Install the antenna at the farthest point from control modules.
Install the antenna fe ...