Abstract: A method for detecting a low level of refrigerant circulating through a motor vehicle refrigerant circuit having a compressor (12), a condenser (14), an evaporator (16), and an accumulator (18), includes detecting a partial loss of a refrigerant fluid by measuring the temperature difference of the refrigerant fluid between an evaporator inlet and an evaporator outlet. The method further includes detecting a complete loss of refrigerant by measuring the pressure of the refrigerant in the liquid phase between the condenser (14) and the evaporator (16). The temperature and pressure measurements are converted to engineering units and then compared to predetermined engineering units that correspond to separate ranges of ambient temperatures for determining the if the refrigerant level is low.