Check The System Pressure
WARNING: This page is about a different car, the 2001 Subaru Forester and 2000 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.
With gauges connected to the A/C system, operate the A/C and confirm that the high side pressure is above 690 kPa (7.03 kg/cm2 , 100 psi). If not, evacuate and charge the system before leak checking. See EVACUATING AND CHARGING .