Smeg oven shows Er04 and beeps; some or all heating functions are disabled.

Safety first: Switch off power at the breaker before removing the control panel.

• Power reset: Turn off the oven at the mains for 5–10 minutes to allow the electronics to discharge. Restore power and check if Er04 clears. If it returns immediately, continue.
• Clean the fascia: Wipe the glass control panel with a soft, dry cloth. Remove any spills, grease, or cleaning residues that may bridge touch keys. Avoid spraying liquid directly onto the panel.
• Check for moisture: If the error appeared after heavy steam cooking or cleaning, leave the oven powered off with the door open for several hours to dry out. Gentle ventilation can help.
• Inspect internal connections: Remove the front control panel to access the touch control PCB and ribbon cable. Check for corrosion, loose connectors, or burnt components. Reseat the ribbon cable between the touch panel and main control board.
• Replace faulty panel: If certain keys do not respond or the error persists despite dry, clean conditions and good connections, replace the touch control PCB or complete glass control panel assembly with the correct Smeg part.