A method to control an electronic throttle valve ETV of a transport refrigeration unit comprising a compressor, a condenser, an expansion device and an evaporator forming a refrigeration circuit, wherein the ETV is positioned in-line between the evaporator and the compressor, the method comprising: determining whether there is a risk of the compressor of the transport refrigeration unit being flooded by liquid refrigerant; closing down the ETV when there is a risk of the compressor being flooded by liquid refrigerant; and opening up the ETV where there is no risk of the compressor being flooded by liquid refrigerant, wherein the ETV is configured to regulate a refrigerant flow into the compressor of the transport refrigeration unit, and wherein determining whether there is a risk of a compressor of the transport refrigeration unit being flooded by liquid refrigerant includes: measuring a refrigerant discharge temperature from the compressor; comparing the refrigerant discharge temperature to a saturated discharge temperature of the refrigerant; when a difference between the refrigerant discharge temperature and the saturated discharge temperature of the refrigerant is below or equal to a threshold value, determining that there is a risk of compressor being flooded; and when the difference between the refrigerant discharge temperature and the saturated discharge temperature of the refrigerant is higher than the threshold value, determining that there is no risk of compressor being flooded. determining whether there is a risk of the compressor of the transport refrigeration unit being flooded by liquid refrigerant; closing down the ETV when there is a risk of the compressor being flooded by liquid refrigerant; and opening up the ETV where there is no risk of the compressor being flooded by liquid refrigerant, wherein the ETV is configured to regulate a refrigerant flow into the compressor of the transport refrigeration unit, and wherein determining whether there is a risk of a compressor of the transport refrigeration unit being flooded by liquid refrigerant includes: measuring a refrigerant discharge temperature from the compressor; comparing the refrigerant discharge temperature to a saturated discharge temperature of the refrigerant; when a difference between the refrigerant discharge temperature and the saturated discharge temperature of the refrigerant is below or equal to a threshold value, determining that there is a risk of compressor being flooded; and when the difference between the refrigerant discharge temperature and the saturated discharge temperature of the refrigerant is higher than the threshold value, determining that there is no risk of compressor being flooded. measuring a refrigerant discharge temperature from the compressor; comparing the refrigerant discharge temperature to a saturated discharge temperature of the refrigerant; when a difference between the refrigerant discharge temperature and the saturated discharge temperature of the refrigerant is below or equal to a threshold value, determining that there is a risk of compressor being flooded; and when the difference between the refrigerant discharge temperature and the saturated discharge temperature of the refrigerant is higher than the threshold value, determining that there is no risk of compressor being flooded.