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

Cabin temperature sensor removal/installation
Evaporator temperature sensor removal/installationMazda 6 Service Manual: Starting a Flooded Engine
If the engine fails to start, it may be flooded (excessive fuel in the engine).
Follow this procedure:
1. If the engine does not start within five seconds on the first try, wait ten
seconds and try again.
2. Make sure the parking brake is on.
3. Depress the accelerator all the way and hold it ...
Mazda 6 Service Manual: Location index
INTAKE-AIR SYSTEM
FUEL SYSTEM
Engine Room Side
Fuel tank side
EMISSION SYSTEM
Engine room side
CONTROL SYSTEM
...