Unit stops and displays E4; may occur during heating or cooling changeover on heat pump models.

Safety first: Disconnect power at the breaker. The fan blades can start unexpectedly if power is present.

• Check for obstructions: Remove the front panel and filters. Spin the cross-flow fan (drum fan) by hand. It should rotate freely without scraping. Remove any debris, dust buildup, or foreign objects.
• Clean the fan: Heavy dirt can overload the motor. Use a soft brush and vacuum to clean the fan wheel and surrounding housing.
• Inspect motor wiring: Open the control box and locate the indoor fan motor connector (usually 3–5 wires). Ensure it is fully seated and wires are not damaged.
• Test motor operation: Restore power and run the unit with the front cover in place. If the fan does not start or starts then stops and E4 appears, the motor or drive circuit is suspect.
• Replace motor: If the fan is stiff or noisy when spun by hand, or shows visible overheating, replace the indoor DC fan motor assembly with a Sharp-compatible part.
• PCB fault: If a new motor still triggers E4, the indoor main PCB fan driver is likely defective and requires replacement.