If an error code like H4 returns immediately after a reset, it usually indicates a hardware failure (such as a blown fuser lamp or faulty thermistor) that requires physical repair.
Type the main code on the numeric keypad and press Start . how to reset sharp ar-6020
Enter sub-code and press Start to clear the sensor error. Restart the printer using the CA button. What to Do If the Error Persists If an error code like H4 returns immediately