E4 error appears and the cooker will not start or stops mid-cycle.

Safety first: Ensure the cooker is unplugged and fully depressurised before working near the lid or steam path.

• Clean steam release components: Remove the steam release valve cap and anti-block shield (if fitted) from the underside of the lid. Wash them in warm soapy water, rinse, and dry thoroughly. Blockages can cause abnormal pressure readings.
• Inspect the pressure sensor port: On many Lakeland multicookers, a small channel or tube from the lid or inner chamber leads to the pressure sensor. Check for food residue or starch blocking this port and gently clear it with a soft brush or wooden toothpick (never metal).
• Dry out condensation: If the cooker has recently boiled over, moisture may have entered the sensor area. Leave the cooker open in a warm, dry place for 24 hours, then test again.
• Check for lid damage: A warped lid or damaged sealing ring can cause unstable pressure, triggering E4. Inspect the silicone ring and lid for deformation and replace if necessary.
• When to replace: If cleaning and drying do not clear E4, the pressure sensor module or its wiring is likely defective and should be replaced. This is an internal, low-voltage component mounted on the control board or lid assembly and is best serviced by a professional.