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

Safety first: Unplug the cooker and let it cool for at least 30 minutes. Do not attempt to bypass any safety devices.

• Check inner pot contact: Ensure you are using the original Tristar inner pot. Make sure the bottom is clean, not warped, and sits flat on the heating plate. A warped pot can cause localized overheating.
• Clean the heating surface: Remove any burnt residue or oil from the heating plate. Even a thin layer of burnt food can cause hot spots.
• Check ventilation: Confirm that the cooker is not pushed against a wall and that side and bottom vents are not blocked by cloths or other appliances.
• Power reset: After cooling and cleaning, plug the unit back in and try a short program with water only. If E4 clears and the unit heats normally, monitor for recurrence.
• Advanced inspection: If E4 persists, the internal thermal fuse or thermostat may be open. Accessing and testing these components requires opening the base and using a multimeter; this is best done by a qualified technician.

Do not bypass or short the thermal fuse or thermostat; they are critical safety components. Replace them with the correct Tristar-rated parts if faulty.