Wolf CI Induction Cooktop Code E40: generator board relay problem

What E40 means

Wolf CI induction cooktops with the 2015-and-newer EGO control, for example the CI304T/S and CI243C/B, display E40 when the generator board reports relay trouble. The relay that switches power to the induction generator is not behaving as expected, and the published guidance is to replace the generator. Owners see E40 and lose heating on the affected zones. Other zones may or may not keep heating, depending on the cooktop.

Common causes of E40

Generator board relay not switching correctly
Generator board needing replacement
Supply interruption that stressed the relay

✓ One safe check you can try

1. Turn all zones off and let the surface cool. 2. Turn the unit's breaker off for one minute, then restore power. 3. Try one zone with a flat, magnetic pan centered on it. 4. If E40 appears again, stop and schedule service. Do not remove the glass or reach into the cabinet.

! Why to stop there

This is a power-section repair, and the generator is not a part to test with a household meter.
Induction generators carry high energy, so we work only with the unit isolated.
We confirm the diagnosis and quote the price before ordering the generator.
Our fix carries a 30-day workmanship warranty.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Cooktop codes

E7Wolf Induction Cooktop Code E7: Keyboard Diode Configuration Error E8Wolf CT Induction Code E8: no communication with generator 1 E9Wolf CT Cooktop Code E9: Generator 2 Communication Error E00Wolf CI Touchscreen and Integrated Module Cooktops Code E00: Overvoltage or No Error E5Wolf CT Induction Code E5: open ambient thermistor and lock mode E1Wolf CT Induction Code E1: ambient temperature too high around the cooktop E50Wolf Induction Code E50: Open Heat Sink Thermistor on a Generator E10Wolf Induction Code E10: generator 3 not responding to the control

E40E40 questions

Does E40 always mean a new generator?

The published direction is to replace the generator when E40 persists. We still confirm the code first, since a one-off event can clear with a reset.

Is it a cookware issue?

E40 points at a relay on the generator board, not at your pans. Pan quality can matter for other induction codes, but here the cause is inside the unit.

Can I use the other burners?

If they heat, they work, but a relay problem can recur without warning. We recommend not relying on the cooktop until it has been checked.