Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Remove the two wires from terminals 3 and 4 to the outdoor sensor and make safe
(left hand side of terminal block, refer to picture)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Has the fault code F39 for the outdoor sensor cleared?