How to fix dyson hot cool AM05 fan displaying E8 code?

Unit can no longer heat at any fan speed other than the lowest setting and will frequently switch itself off and display an E8 error code. This behaviour happens even when set to highest temperature (It's not switching off because ambient temperature is already higher than the device's desired temperature).

I have called Dyson and they advise it will need a service and that E codes relate to motor or temperature sensor. That may be the case, but I would at the very least like to know what E8 specifically means and they said that only the technicians know that.