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: Precaution
Vehicles with ABS/TCS
1. The ABS warning light, BRAKE system warning light, TCS indicator light
and/or TCS OFF light illuminate even when the system is normal.
*1 : In cases where the light may illuminate, only when ABS/TCS HU/CM detects
that speed sensor of rear wheel is malfunctioning.
*2 ...