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: Foreword
Outline
There are two on-board diagnostic functions: Operation mode, which
inspects for and indicates correct operation of the input signals to the
control module, and condition detection mode, which indicates troubles in
the system.
The two functions can be done using either of the f ...
Mazda 6 Service Manual: Range of topics
This manual contains procedures for performing all required service
operations. The procedures are divided into the following five basic
operations:
Removal/Installation
Disassembly/Assembly
Replacement
Inspection
Adjustment
Simple operations which can be perf ...