E4 appears on the display and the cooker will not start pressure or high-heat programs.

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

• Clean pressure path: Remove the inner lid and clean the steam release valve, anti-block shield, and pressure channel with warm water and a soft brush. Blockages can cause abnormal readings.
• Locate pressure sensor: On many AEG multicookers, the pressure sensor is mounted on the main PCB and connected via a small silicone tube to the lid or steam channel. Check that the tube is not kinked, cracked, or disconnected.
• Inspect sensor connector: Ensure the pressure sensor's electrical connector is firmly seated on the PCB and free of moisture or corrosion.
• Test with water-only cycle: Reassemble, add water to the max 1/2 mark, and run a pressure program. If E4 appears before pressure builds, the sensor is likely faulty.
• Replace pressure sensor: If tubing and channels are clear and wiring is intact, replace the pressure sensor module. If E4 persists even with a new sensor, the main control PCB may be defective and should be replaced by a professional.