Microwave beeps and shows E03; cooking does not start.

Safety first: Disconnect the appliance from mains power before removing any panels.

• Step 1 – Power reset: Unplug the microwave for 5–10 minutes to discharge the control board. Plug back in and check if E03 clears.
• Step 2 – Inspect keypad area: Check for signs of liquid spills or steam damage around the control panel. Wipe the surface dry and allow the unit to air-dry for several hours if moisture is suspected.
• Step 3 – Check ribbon cable: Remove the control panel fascia (usually held by screws behind the door frame). Locate the flat ribbon cable from the keypad to the PCB. Gently unplug and reinsert it, ensuring it is fully seated and not creased or torn.
• Step 4 – Test keypad response: With the unit reassembled and powered, test multiple buttons. If some or all keys are unresponsive and E03 returns, the membrane keypad or complete control panel assembly likely needs replacement.
• Step 5 – Replace control PCB if needed: If a known-good keypad still triggers E03, the main control PCB is likely defective and should be replaced or serviced by a technician.