--- title: "Wolf CE electric cooktop showing U400 | CooktopRepair.center" description: "What U400 means on Wolf CE electric cooktops, what to check before booking, and when it is not a failure at all." url: "https://cooktoprepair.center/error-codes/wolf-u400/" --- # Wolf CE electric cooktop showing U400 U400 on a Wolf CE electric cooktop means over voltage: the supply reaching the cooktop is higher than it should be. ## What U400 actually means. U400 on a Wolf CE electric cooktop means over voltage: the supply reaching the cooktop is higher than it should be. The cause is usually in the wiring or the supply, not inside the cooktop. Wolf cooktop display What to do when U400 shows on the cooktop ### Kind of code Boards and communication The touch board and the power board under the glass lost track of each other, or one failed its own start-up check. A power dip, a ribbon or harness pulled loose when the top was fitted, or moisture from a boil-over is ruled out before a board is replaced, and a cooktop that keeps heating while this code shows is switched off at the breaker. ### Usually leads to Touch control repair Glass touch keys and sliders that ignore a finger, start zones by themselves or stay locked, traced to the keys, the control board or the lock setting. ### Shows up as Cooktop Tripping Breaker The circuit breaker for the cooktop trips as a burner or zone switches on, at one particular setting, or a few minutes into cooking. ### Make Wolf The cooking half of Sub-Zero Group, selling cooktops and rangetops from its Wisconsin base. ### Source Wolf answer: CE electric cooktop, error code U400 Wolf CE series electric cooktops. ## Before you book, in this order. Each step comes from Wolf's own guidance for U400 on its cooktops. Follow it to the end: the last card says whether this is a visit. 01 Switch the cooktop off at its breaker and leave it off. 02 Have the circuit and the cooktop connection checked; after that, a 30-second breaker reset is Wolf's only home step. 03 Book a visit if U400 shows again with a confirmed supply. ### Still there? It usually turns into [touch control repair](https://cooktoprepair.center/services/touch-control-repair/). Book with the code and the model number. ### What not to do U400 is not a sign of a failed element or keypad. It reports the power coming in. ## What you may notice with it. The cooktop problems U400 tends to arrive with. Answer these at the cooktop before anyone is booked. [All problems](https://cooktoprepair.center/problems/) Before you call ### [Cooktop Tripping Breaker](https://cooktoprepair.center/problems/cooktop-tripping-breaker/) [All 6 causes, cheapest first](https://cooktoprepair.center/problems/cooktop-tripping-breaker/) It also comes with - [**Cooktop Error Code**](https://cooktoprepair.center/problems/cooktop-error-code/) Gas, fire, broken glass or live current ### Cooktop Tripping Breaker 6 causes, cheapest first Where U400 usually leads ## Touch control repair. **Touch control board or key panel · moderate.** Book a visit [What the job involves](https://cooktoprepair.center/services/touch-control-repair/) ## Wolf cooktops. The cooking half of Sub-Zero Group, selling cooktops and rangetops from its Wisconsin base. [Wolf cooktop repair](https://cooktoprepair.center/brands/wolf/) More Wolf codes [3](https://cooktoprepair.center/error-codes/wolf-3/) [E22](https://cooktoprepair.center/error-codes/wolf-e22/) [E1](https://cooktoprepair.center/error-codes/wolf-e1/) [E3](https://cooktoprepair.center/error-codes/wolf-e3/) [E4](https://cooktoprepair.center/error-codes/wolf-e4/) [E9](https://cooktoprepair.center/error-codes/wolf-e9/) [E43](https://cooktoprepair.center/error-codes/wolf-e43/) [E44](https://cooktoprepair.center/error-codes/wolf-e44/) [F7](https://cooktoprepair.center/error-codes/wolf-f7/) [E8](https://cooktoprepair.center/error-codes/wolf-e8/) [E5](https://cooktoprepair.center/error-codes/wolf-e5/) [EA](https://cooktoprepair.center/error-codes/wolf-ea/) [All 15 Wolf codes](https://cooktoprepair.center/error-codes/#codes-wolf) Boards and communication on other makes [BlueStar E](https://cooktoprepair.center/error-codes/bluestar-e/) [Bosch E7010](https://cooktoprepair.center/error-codes/bosch-e7010/) [Café F + number (flashing)](https://cooktoprepair.center/error-codes/cafe-f-code/) [Dacor F0](https://cooktoprepair.center/error-codes/dacor-f0/) [Frigidaire C0](https://cooktoprepair.center/error-codes/frigidaire-c0/) [Fulgor Milano Er47](https://cooktoprepair.center/error-codes/fulgor-milano-s700-er47/) [Gaggenau E7010](https://cooktoprepair.center/error-codes/gaggenau-e7010/) [GE Profile F + number (flashing)](https://cooktoprepair.center/error-codes/ge-profile-f-code/) [All 47 codes of this kind](https://cooktoprepair.center/error-codes/#family-communication) Wolf builds this ### Gas cooktop A gas cooking surface dropped into a countertop cutout, with its gas line and power cord running down into the cabinet underneath. Wolf builds this ### Electric cooktop A coil or smooth-glass radiant cooking surface built into the countertop and wired to its own circuit in the cabinet or wall behind it. Wolf builds this ### Induction cooktop A glass cooktop in the counter that heats the pan itself through magnetic coils, run by power boards and cooled by a fan underneath. ## In Wolf's own words > Over voltage [Wolf answer: CE electric cooktop, error code U400](https://www.subzero-wolf.com/assistance/answers/wolf/ce-electric-cooktop/ce-electric-cookop-series-error-code-u400) [Wolf answer: CE electric cooktop, error code U400](https://www.subzero-wolf.com/assistance/answers/wolf/ce-electric-cooktop/ce-electric-cookop-series-error-code-u400) Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. Wolf CE series electric cooktops. ## Wolf U400 cooktop repair, where we come out. The same visit in every metro below: the code, the model number, and a diagnosis before any part is ordered. 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Switch the cooktop off at its breaker and leave it off. If it comes back, it needs a visit. ### What causes U400 on a Wolf electric cooktop? Wolf lists over voltage. A miswired connection at the cooktop or a supply problem in the home are the usual suspects, so the circuit is checked first. ### Should I keep resetting the breaker when U400 appears? No. One reset after the supply has been checked is enough; repeated resets on a supply problem risk the cooktop electronics. ### Can a new installation lead to U400 on a Wolf CE electric cooktop? It can, because U400 reports over voltage and a connection made wrong at the cooktop is one way to get it. If the code first showed after the top was installed or rewired, have that connection checked before anything else. --- **[Read on the site: Wolf CE electric cooktop showing U400 | CooktopRepair.center](https://cooktoprepair.center/error-codes/wolf-u400/)** **[Book a visit with CooktopRepair.center](https://cooktoprepair.center/schedule/)**