E4 error appears when trying to start a pressure program; cooker does not build pressure and cancels the cycle.

Safety first: Ensure the cooker is unplugged and fully depressurized before handling the lid. Never force the lid open under pressure.

• Inspect lid seal: Remove the silicone sealing ring from the lid. Check for cracks, deformation, or food buildup. Clean thoroughly and refit, ensuring it is evenly seated in the groove.
• Check steam release valve: Remove the steam release cap (if removable) and clean any food residue. Ensure the valve moves freely between sealing and venting positions.
• Examine lid sensor wiring: On models with a detachable lid connector, unplug and replug the lid sensor connector several times to clean the contacts. On hinged lids, inspect the flex cable for kinks or breaks.
• Test lid sensor (if accessible): If you can access the lid NTC, measure its resistance at room temperature and compare with the bottom sensor. A reading of 0 Ω (short) or infinite (open) indicates a failed sensor that must be replaced.

If E4 persists after cleaning and reseating the seal and connectors, the lid sensor or main PCB should be replaced by a qualified service technician.