AGA Elise or Mercury induction range
showing U400
U400 means the induction range has been wired wrongly.
Mon–Sat, 8am–8pm
- Controls and communication
- Knobs, switches and controls
- Source: AGA
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What U400
actually means.
U400 means the induction range has been wired wrongly. The control switches off after about a second and the code stays on the display permanently until the connection is corrected.
AGA range display
What to do when U400 shows on the rangeKind of codeControls and communication
The display, the main board or the induction power board lost contact with one another, or one of them failed its own self-check. A power dip, a loose cable or moisture from a boil-over is ruled out before a board is replaced, and a range that keeps heating while this code shows is switched off at the breaker.
Usually leads toKnobs, switches and controls
Knobs that spin or crack, touch keys that do nothing, blank displays, clocks that reset and control boards that switch the wrong thing.
Shows up asRange Error Code
The range display shows letters, numbers or a flashing symbol, beeps, and stops the oven, a cooking zone or a clean.
MakeAGA
A British cooking name, owned by Middleby, that sells cast-iron heat-storage cookers and more conventional dual-fuel and induction ranges in the US.
SourceAGA Elise 36 Induction Owner's Guide
Elise and Mercury induction ranges; usually seen at first power-up after installation or after electrical work.
Before you book,
in this order.
Each step comes from AGA's own guidance for U400 on its ranges. Follow it to the end: the last card says whether this is a visit.
Switch the range off at the breaker and leave it off.
Book a visit to have the electrical connection checked; do not keep resetting it.
Still there?
It usually turns into knobs, switches and controls. Book with the code and the model number.
What not to do
U400 is not caused by cookware or cooking habits, and it will not clear with use.
What you may
notice with it.
The range problems U400 tends to arrive with. Answer these at the range before anyone is booked.
All problems
Range Error Code
6 causes, cheapest first
Where U400 usually leads
Knobs, switches and controls.
AGA
ranges.
A British cooking name, owned by Middleby, that sells cast-iron heat-storage cookers and more conventional dual-fuel and induction ranges in the US.
AGA range repairMore AGA codes
All 21 AGA codesControls and communication on other makes
Electric range
Coil elements or radiant elements under a smooth glass top, with an electric oven below, all running on a dedicated 240-volt circuit.
Dual-fuel range
Gas burners on top and an electric oven below, the combination most professional-style ranges use, needing both a gas line and a 240-volt circuit.
Induction range
A glass top that heats the pan itself through copper coils and power boards, over an electric oven, with electronics doing almost all the work.
In AGA's own words
The range has been incorrectly connected.
Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. Elise and Mercury induction ranges; usually seen at first power-up after installation or after electrical work.
AGA U400 range 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?
My new AGA Elise shows U400 right away. What went wrong?
Is it safe to keep resetting U400 on an AGA Mercury?
Back to your everyday
Still showing U400?
Book with the code exactly as it appears, the full model number, and whether you notice any smell of gas or scorching — with a code, that is where the diagnosis begins.