F51 error; gas cooktop burners ignite but clicking continues, or flame detection unreliable.

Safety: Turn off gas and power before touching electrodes.

• Clean sensor: Identify the flame sensor electrode (often combined with spark electrode). Clean with a soft brush or fine abrasive pad to remove carbon and grease.
• Check alignment: Ensure the sensor tip is in the flame path when the burner is lit.
• Grounding: Verify that burner bases are properly seated and that mounting screws are tight to provide a good ground path.
• Dry thoroughly: If recently cleaned, allow all components to dry completely.
• Module replacement: If the sensor and grounding are correct but F51 persists, replace the ignition/flame supervision module.