Gree Mini Split F4 Error Code

What F4 means

F4 means the controls cannot trust the outdoor condenser (coil) temperature sensor reading - open, shorted, or out of range. On some Gree wall-mount ranges the F-series shifts by one position and F4 instead identifies the compressor discharge temperature sensor; the common thread is an outdoor-side temperature sensor circuit fault requiring technician diagnosis.

Causes, ranked

1. 1. Outdoor condenser coil temperature sensor open or shorted common pro only

   Check: Needs resistance measurement against the service-manual sensor table.

   Fix: Technician: test and replace the outdoor coil sensor if out of spec.

2. 2. Dirty outdoor coil or blocked airflow overheating the sensor area common DIY

   Check: Check leaves, snow, and debris around the outdoor unit and wash indoor filters; confirm 12+ in clearance.

   Fix: Clean filters and coil surroundings, power cycle once; if F4 returns, stop.

3. 3. Loose sensor connector or corroded sensor lead occasional pro only

   Check: Connector inspection is inside the outdoor electrical box.

   Fix: Technician: reseat or repair the sensor wiring.

4. 4. Outdoor board sensor-input fault after the sensor tests good rare pro only

   Check: Board-level diagnosis only.

   Fix: Technician: diagnose the outdoor PCB input; replace board if faulty.