The E04 error code on a Blomberg washing machine generally indicates a problem with the water filling. It's either the machine is not filling at all or it's filling too slowly.
To resolve this issue, follow these steps:
1. Check if the water supply is turned on and the water pressure is adequate.
2. Inspect the hoses for any kinks or damage that could be restricting water flow. If any are found, straighten the hose or replace it as necessary.
3. Clean the water inlet filters. They may be clogged with debris or limescale.
4. If the problem persists, there might be a problem with the water inlet valve or the pressure switch. In such cases, it is recommended to contact a service technician for further assistance.