E4 appears on the display, often when trying to use pressure cook modes.

Safety first: Ensure the cooker is unplugged and fully depressurized before inspecting the lid or pressure components.

• Clean and inspect lid: Remove the lid and clean around the locking mechanism, float valve, and any sensor areas. Food residue can prevent proper sensor operation.
• Check lid orientation: Reinstall the lid according to the alignment marks on the housing and lid. Make sure it is fully rotated to the LOCK position until it clicks.
• Test different modes: Try a non-pressure mode (e.g., Sauté or Brown). If E4 only appears in pressure modes, the pressure sensor or lid switch is suspect.
• Inspect lid connector (if present): On models with an electrical connector between lid and body, inspect the pins for bending, corrosion, or food buildup. Clean gently and ensure a snug fit.
• Check wiring (advanced): With the unit unplugged and base removed, trace the lid sensor harness to the main control board. Ensure all connectors are fully seated and wires are not pinched.
• Reset: After cleaning and reseating, plug in and attempt a short pressure cycle with adequate liquid. If E4 persists, the sensor or board may be defective.
• Replacement: Replace the lid assembly with integrated lid switch/pressure sensor if available as a complete part. If the sensor is board-mounted, the main control board may require replacement by a technician.