E221 relates to the outdoor unit’s ambient temperature sensor, which measures the outside air temperature so the system can adjust its operation accordingly. An open or short circuit at this sensor stops the outdoor board from getting a reliable reading, and the unit responds by raising the fault.
This sensor might seem minor, but the outdoor board uses it to fine-tune compressor and fan behaviour across different weather conditions, so a faulty reading can affect how the whole system performs. It’s usually a straightforward sensor issue rather than a sign of a bigger fault.
Send us the code and a photo of the display, and a Ford & Doonan technician will get back to you. Please don't reset the unit before you take the photo.
(08) 9331 8800