E4 appears on the display, often when using pressure or high-temperature frying modes.

Safety first: If the cooker is under pressure, do not attempt to open the lid. Unplug the unit and allow it to cool until the float valve drops and pressure is fully released.

• Clean steam release valve: Remove the steam release valve cap on the lid (if removable on your Oursson model). Wash it under warm water, clearing any food particles or starch. Ensure the vent path is unobstructed.
• Inspect anti-block shield: Many Oursson pressure multicookers have a metal anti-block shield under the valve. Remove it (usually clips off) and clean thoroughly. Reinstall securely.
• Check sealing ring: Remove the silicone sealing ring from the lid. Inspect for cracks, deformation, or food buildup. Wash and dry it, then reinstall evenly in its groove. Replace if hardened or damaged.
• Test without food: After cleaning, add about 1–2 cups of water to the inner pot, close the lid, and run a short pressure program. If E4 reappears quickly, the pressure sensor or control board may be faulty.
• Service if persistent: Pressure sensor replacement and calibration should be done by an authorized Oursson service center. Do not continue using the cooker in pressure mode if E4 persists.