E466 relates to the outdoor unit’s internal DC link voltage, the power bus that feeds the inverter and compressor drive with converted DC power. When the voltage on this internal bus falls outside the normal operating range, either too low or too high, the system raises this fault to protect its electronics.
This isn’t a sensor issue so much as a power-quality one, meaning the root cause can sit anywhere from the mains supply coming into your home through to a fault on the inverter board itself. It’s worth ruling out the simpler external causes before assuming the worst.
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