E4 error appears when trying to start a pressure-cooking program; unit may beep and cancel.

Safety first: Ensure the cooker is unplugged and fully depressurized before touching any pressure components.

• Clean steam valve: Remove the steam release valve cap (if removable on your Tefal model). Clean it under warm water to remove starch buildup. Ensure the float valve and anti-block shield are free of debris.
• Inspect pressure lid components: Check the silicone gasket, float valve, and safety pin for free movement. Replace the gasket if it is cracked, flattened, or hardened.
• Check sensor area: On models with a visible pressure sensor port in the lid or body, ensure it is not blocked by dried food. Clean gently with a toothpick or soft brush.
• Reset and test: Reassemble all parts, plug in, and test with water only (no food). If E4 appears again without building pressure, the pressure sensor or its wiring is likely faulty.
• Service action: Replacement of the pressure sensor module or lid assembly is usually required and should be done by a qualified technician due to safety implications.