Upon arrival saw thermostat code (A929_O 240V Missing or inverter comm failure). Went to outdoor unit tested voltage for disconnect, contactor and transformer received 240. Checked communication wires and wire nuts, checked continuity through communication wires. Checked molex plugs on drive board for voltage got 240. Checked molex plugs on control board and drive board to make sure they were secure. Turned off outdoor and indoor units for 15 mins to do a hard reset, turned back on checked thermostat still giving code from arrival, cleared fault on thermostat, fault immediately came back. Homeowner wants a portable until drive board gets replaced, told her I could do it tomorrow afternoon.