E04 appears during preheat or pressure build; cooker stops heating

Safety first: Unplug the cooker and ensure it is fully depressurized. Never attempt to open the lid while under pressure.

• Clean steam release valve: Remove the steam release knob/valve from the lid. Soak it in warm soapy water and clear any food particles from the vent path with a soft brush.
• Clean float valve and anti-block shield: Remove the anti-block shield (small metal or plastic cover under the lid) and clean it thoroughly. Push the float valve up and down; it should move freely. Clean around the float with a brush.
• Check gasket condition: Inspect the silicone lid gasket for swelling, cracks, or food buildup. Clean it and the gasket groove; replace if deformed.
• Inspect pressure release mechanism: Ensure the spring-loaded safety valve (if accessible) is not stuck. Lightly press it from inside the lid to confirm free movement.
• Test with water: Reassemble, add water to the inner pot, and run a short pressure program. Watch for normal steam release and absence of E04.

If E04 persists with a clean valve system, the pressure sensor or control board may be misreading pressure and should be checked by a technician.