Electronic cooktop or range display shows E0 and none of the touch keys respond or only power key works intermittently.

Safety first: Disconnect the range or cooktop from mains power by switching off the circuit breaker or unplugging. Confirm that all indicator lights are off before opening any panels.

• Access the control area: Remove the rear control panel cover (for freestanding ranges) or the underside/side panels (for built-in cooktops) using a suitable screwdriver.
• Inspect ribbon cable: Locate the flat ribbon cable from the glass touch panel to the main control PCB. Check for kinks, burns, or partial disconnection. Reseat both ends carefully, ensuring the locking tabs are fully engaged.
• Clean connectors: If you see oxidation or grease, gently clean the ribbon contacts with isopropyl alcohol and a lint-free cloth. Allow to dry fully before reconnecting.
• Check for moisture: Look for signs of liquid ingress around the touch panel. If moisture is present, dry the area thoroughly and leave the unit disconnected for several hours.
• Reassemble and test: Refit covers, restore power, and test all keys. If E0 persists, the touch control panel or main control PCB is likely defective and should be replaced with the exact Gram spare part specified for your model.

Warning: Do not work on live circuits. If you are not comfortable opening the appliance, contact a qualified technician.