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: 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: Vehicle speedometer sensor (vss) inspection
Visual Inspection
1. Remove the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS)
REMOVAL/INSTALLATION.)
2. Make sure that the sensor is free of any metallic shavings or particles.
If any are found on the sensor, clean them off.
3. Install the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS)
REMOVAL ...