1. After receiving the vehicle, the fault diagnosis instrument V.A. S5051 was used for detection, and the fault code was found to be 00229, meaning that the pressure of the refrigeration system was lower than the lower limit value. The air conditioning pressure gauge is connected to measure the static pressure of the air conditioning system as 550kPa, indicating that the pressure is too low. Try to release the refrigerant from the line through the refrigerant gauge. The result is only air, which means there is no refrigerant in the air conditioning line. Since the vehicle USES a variable displacement compression machine, it is necessary to determine the fault point by filling refrigerant and reading data flow. Then re-vacuum the air conditioning system and re-fill the refrigerant, found that the injected dose of refrigeration significantly reduced, after the injection of part can not be added. Air conditioning is still not working, touch the low - voltage air conditioning tube no signs of refrigeration.