Expansion Valve
The expansion valve atomizes the flowing refrigerant and controls the flow rate so that the vapor is only gaseous at the evaporator output, depending on the heat transmission.
Be sure to note the correct part number when replacing the expansion valve. Refer to the appropriate Electronic Parts Information.
There are different characteristic curves that correspond to the respective circuit. Refer to Refrigerant Circuit (vehicle-specific repair information) and the appropriate Electronic Parts Information.
Depending on the A/C compressor version, there may be a valve installed on the high pressure side of the A/C compressor, which prevents the liquid refrigerant from flowing back into the A/C compressor once the A/C system is turned off. If an A/C compressor with this valve is installed in a vehicle with a refrigerant circuit having an expansion valve, then it may take some time until the pressure in the high pressure side decreases (the expansion valve is cold and the pressure in the low pressure side quickly increases after it is turned off, the expansion valve closes and the refrigerant can flow slowly to the low pressure side). If the A/C compressor is switched on, the pressure on the low pressure side decreases, the expansion valve opens and the refrigerant can flow to the low pressure side.