DIAGNOSIS F0 indicates a problem with the room temperature sensor or its wiring. This sensor is usually a small thermistor attached to the evaporator coil or nearby. If the control board gets an impossible reading (like -40°F), it throws this code and stops to protect itself.
FIX Unplug the unit and let it sit for 5 minutes. Sometimes a power glitch can cause a temporary sensor misread. Plug it back in. If F0 returns immediately, the sensor itself is likely faulty or has a broken wire. Accessing it requires removing the cabinet. On this model, the sensor is often clipped to a fin on the coil. You'd need to check for continuity with a multimeter.
IF THAT DIDN'T WORK If the sensor checks out, the issue is on the main control board. A failed component on the board can send the wrong voltage to the sensor circuit, mimicking a sensor failure. Board replacement is the fix here.
HEADS UP Don't ignore this and try to keep restarting the unit. An inaccurate temperature reading can cause the unit to run the compressor in conditions that can damage it, leading to a much costlier repair.