E4 indicates that the Haier washer-dryer is not reaching the expected water level. The available supply, its path, and the detection system must be distinguished before diagnosing a fault.
The Haier USA washer-dryer chart documents that meaning. The chart places this detection after eight minutes without reaching the selected level in those washer-dryers. That time limit does not apply to the brand as a whole.
If it started after an installation or a power outage
Check that the water has been restored and that the washer-dryer faucet is open. Look for kinked hoses and confirm the number of inlets required by the manual, without copying connections from another market.
If the supply seems normal but E4 appears again, do not conclude that the sensor is broken. The fill circuit may need to be inspected; visible water alone also does not prove that the expected level has been reached.
Accessible screens should only be cleaned according to the manual, with the shutoff valves closed and the unit electrically isolated. Do not open valves or add water through the drawer to bypass the alarm.
If your display says Err5, keep that wording and look up its series; matching symptoms do not mean equivalence across all platforms.
Tell support whether little water enters, no water enters, or water enters without the program advancing; each observation narrows a different hypothesis.