Bosch cooktop
showing U400
U400 reports a supply voltage that is too high or too low for the cooktop.
Mon–Sat, 8am–8pm
- Induction power and coils
- Induction board and coil repair
- Source: Bosch
Book a visit
Three short steps, about a minute.
or call (844) 252-4077
Loading appointment form…
The appointment form couldn’t load. Please try again.
What U400
actually means.
U400 reports a supply voltage that is too high or too low for the cooktop. The problem sits in the circuit feeding the cutout, not in the zones.
Bosch cooktop display
What to do when U400 shows on the cooktopKind of codeInduction power and coils
An induction zone could not drive its coil as the board planned: no pan was detected, the current ran too high or too low, or the power stage reported trouble. The pan base, the supply voltage and a clogged air intake are checked before the coil or the power board is replaced, and a top that trips its breaker is left switched off until then.
Usually leads toInduction board and coil repair
Induction zones that stop sensing pans, cut out, buzz or show codes, traced to the power boards, the coils, their sensors and the links to the controls.
Shows up asCooktop 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.
MakeBosch
A German maker whose US site lists gas and induction cooktops for building into the counter.
SourceBosch cooktop and rangetop error codes (US support)
Listed for Bosch electric and induction cooktops; Bosch pairs it with E9011 for a wiring mistake.
Before you book,
in this order.
Each step comes from Bosch's own guidance for U400 on its cooktops. Follow it to the end: the last card says whether this is a visit.
Switch the cooktop off at the breaker and leave it off.
Do not open the junction box below the cooktop yourself; leave the measurement to the electrician.
Have an electrician or the utility check the supply; book a visit once the voltage is known to be normal and U400 remains.
Still there?
It usually turns into induction board and coil repair. Book with the code and the model number.
What not to do
U400 is not a pan or zone code, and using the cooktop anyway is not a fix. It is a report about the supply feeding the cooktop, which the cooktop cannot correct by itself.
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
Cooktop Tripping Breaker
6 causes, cheapest first
Where U400 usually leads
Induction board and coil repair.
Bosch
cooktops.
A German maker whose US site lists gas and induction cooktops for building into the counter.
Bosch cooktop repairMore Bosch codes
Induction power and coils on other makes
Gas cooktop
A gas cooking surface dropped into a countertop cutout, with its gas line and power cord running down into the cabinet underneath.
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.
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 Bosch's own words
The supply voltage is incorrect. It is outside the normal operating range.
Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. Listed for Bosch electric and induction cooktops; Bosch pairs it with E9011 for a wiring mistake.
Bosch 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.
All service areasTampa BayFL · 31 areas
Miami / South FloridaFL · 47 areas
New York MetroNY · 75 areas
HoustonTX · 36 areas
ChicagoIL · 50 areas
Los AngelesCA · 95 areas
San DiegoCA · 31 areas
Questions
about U400.
Can I clear U400 myself?
Who should look at U400 on a Bosch cooktop first?
Can a loose connection under the counter cause U400?
Does Bosch pair U400 with E9011 for a reason?
Back to your everyday
Still showing U400?
Book with the code copied exactly, the full model number, and whether there is any smell of gas or burning — with a code in hand, that is where the diagnosis starts.