Method for providing a diagnostic on a combined humidity and temperature sensor

A system, comprising:

• a combined humidity and temperature sensing device including a temperature sensor, a humidity sensor having a humidity sensing element, and a heater;
• an additional temperature sensor different from the temperature sensor of the combined humidity and temperature sensing device, the additional temperature sensor is arranged so as not to be affected by the heater;
• and
• a processor performing the steps of:
• obtaining a first temperature and a first relative humidity output by the combined humidity and temperature sensing device, the first relative humidity is a function of the first temperature;
• heating the humidity sensing element with the heater;
• obtaining a second temperature and a second relative humidity output by the combined humidity and temperature sensing device after heating the humidity sensing element, the second relative humidity is a function of the second temperature;
• determining a difference between the first temperature and the second temperature and a difference between the first relative humidity and the second relative humidity;
• outputting diagnostic information representative of a possible malfunction of the humidity sensor when the difference between the first temperature and the second temperature is higher than a predetermined temperature difference threshold and the difference between the first relative humidity and the second relative humidity is lower than a predetermined humidity difference threshold;
• and
• outputting a degraded mode information if a possible malfunction of the temperature sensor is determined, the degraded mode information including an external temperature output from the additional temperature sensor and a relative humidity output by the combined humidity and temperature sensing device as a function of the external temperature.