The E1 error code on your Haier air conditioning unit indicates a communication error between the indoor and outdoor units. This can result in the system being unable to operate effectively.
If the wiring between the indoor and outdoor units is loose or damaged, it can interrupt communication.
The control board (PCB) in either the indoor or outdoor unit may be malfunctioning.
Voltage fluctuations or power surges can cause communication failure.
Turn off the air conditioner for 5–10 minutes, then turn it back on to reset the communication.
Check the wiring between the indoor and outdoor units for any loose or damaged connections.
If communication continues to fail, the PCB may need to be inspected and replaced by a technician.