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: Cooling system service warnings
COOLING SYSTEM SERVICE WARNINGS
Warning
Never remove the radiator cap or loosen the radiator drain plug
while the engine is running, or when the engine and radiator are hot.
Scalding coolant and steam may shoot out and cause serious injury. It may
also damage the engine and cooling sys ...
Mazda 6 Service Manual: Instrument cluster removal/installation
Caution
When replacing the instrument cluster, the configuration procedure must be
performed before removing the instrument cluster. If the configuration procedure
is not performed before removing the instrument cluster, it is possible that the
instrument cluster will not operate normally. ...