1. Measure the temperature around the water temperature sensor.
2. Measure the resistance between terminals of the water temperature sensor.

Water temperature sensor removal/installation
Refrigerant pressure switch removal/installationMazda 6 Service Manual: Oil pressure switch removal/installation
Warning
When the transaxle and ATF are hot, they can badly burn. Turn off
the engine and wait untill they are cool before replacing ATF.
1. Disconnect the negative battery cable.
2. Remove the under cover.
3. Disconnect the cord assembly connector.
4. Remove the oil pressure switch.
...
Mazda 6 Service Manual: Registering Your Vehicle in A Foreign Country (Except United States and Canada)
Registering your vehicle in a foreign country may be problematic depending on
whether it meets the specific emission and safety standards of the country in which
the vehicle will be driven. Consequently, your vehicle may require modifications
at personal expense in order to meet the regulation ...