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

Safety first: Ensure the cooker is unplugged and fully depressurized. Never attempt to open the lid while under pressure.

• Clean steam release components: Remove the steam release valve cap and anti-block shield (if fitted) from the lid. Wash them thoroughly with warm soapy water, rinse, and dry. Clear any food particles or starch buildup.
• Inspect pressure port: Look into the steam vent opening and around the float valve area for clogs. Use a soft brush or toothpick to gently dislodge residue. Do not enlarge holes.
• Check float valve: Make sure the float valve moves freely up and down and is not stuck with dried food. Clean and reassemble according to the manual.
• Power reset: After cleaning, plug the unit back in and run a water-only pressure test with at least 2 cups of water to see if E4 clears.
• Advanced: If accessible on your model, inspect the small silicone or rubber tube that connects the pressure port to the internal pressure sensor. Ensure it is not kinked, cracked, or blocked.

If E4 persists, the internal pressure sensor or its circuitry is likely defective and requires professional replacement.