There Is Heavy Frost or Condensation On the Expansion Valve, and Frost On the Suction Line

There is heavy frost or condensation on the expansion valve, and frost on the suction line

Probable cause: A restriction in the low-pressure side of the system

Recover A/C refrigerant A/C Refrigerant Recovery, then check the suction line and the expansion valve for restrictions. Repair as needed. Recharge the system to specifications A/C System Charging

Also check for

Climate control DTCs Initial Inspection and Diagnostic Overview