Not sure what you want to know, a mechanic licensed to do A/C work can fix this, all A/c systems will have a expansion valve or also known as at TX valve.
February, 10, 2011 AT 7:14 PM
A/C system without Expansion Valve use an orfice tube called CCOT type. Located in high pressure line just before evaporator. Small plactic screen with small metal tube inside that drops pressure entering evaporator to @33-35 psi.