A La Cornue cooktop is the hob of the cooker, built from brass “flammes” gas burners, induction zones, or both, so its faults are diagnosed differently depending on which technology is acting up. Gas faults are physical indicators: a single burner that will not light, all burners failing to spark (an ignition-module fault), continuous clicking from a wet or dirty electrode, or a low and uneven flame from a clogged orifice. These are read by eye and meter, since a gas burner has no code to show.
How La Cornue cooktop faults are diagnosed
Induction zones, by contrast, report through real codes. A flashing U means no pan or an incompatible non-ferrous pan is detected — but if the correct pan is present and other zones still work, the coil or sensor has failed and needs service. E2 indicates the electronics are too hot or a pan boiled dry, so the technician checks ventilation and the cooling path. U400 flags an incorrect supply connection, and the H indicator simply confirms a zone is still hot. An Er code points to an internal fault on multifunction electronics.
Mechanical service items
Cracked induction glass, a cracked or warped French-top plate, corroded burner caps or grates, a teppanyaki plate that will not heat, a continuously clicking igniter, and a stiff knob are the common mechanical cooktop calls, and the technician confirms which module is at fault before any part is ordered. We match induction coils, sensors, ignition modules, orifices, and grates to your specific hob configuration, because the rangetop is built to order and a combination hob may need both gas and induction expertise on the same visit. The ceramic-glass induction surface and the brass burner caps are also restored with correct materials so the cosmetic finish survives the repair, and a French Top, where fitted, is re-seasoned rather than scoured. Schedule a cooktop repair (from $X), or identify your hob layout in the model lineup first.