What Causes Frosting on the Low-Pressure Pipe of a Car's Air Conditioning System?

[LeRiver]

Car air conditioning low-pressure pipe frosting is caused by a malfunctioning expansion valve. Expansion valve malfunction: If the low-pressure pipe of a car's air conditioning system freezes, it is most likely due to a faulty expansion valve that fails to sense the real-time temperature of the low-pressure pipe. In such cases, if the temperature is too low, the low-pressure pipe will inevitably freeze (the expansion valve's opening cannot be adjusted downward). This issue generally cannot be repaired and requires replacing the expansion valve with a new one. Here is additional information: Evaporator temperature sensor failure: It could also be due to a failed evaporator temperature sensor. This component is responsible for detecting the surface temperature of the evaporator and transmitting the data to the automatic air conditioning control unit. When the temperature drops below 2°C, the air conditioning system stops operating to prevent frost or ice formation. If the evaporator temperature sensor fails, it cannot detect the corresponding temperature data, leading to freezing of the low-pressure pipe. In this case, replacing the sensor is necessary.