Written by
Elena Marsh Appliance Care EditorPublished October 29, 2026
VERIFIED
Error code40
ApplianceCooktop
Forty on the display is a communication error: the main power control board and the filter control board cannot talk to each other.
Quick reference
Item
Detail
Code
40
Boards involved
Main power control board and filter control board
Cooktops
Kenmore induction, 790 model numbers, numeric codes
Remedy as written
The work opens with the cooktop unpowered. Wire harness connections on both boards come under inspection. Sound connections mean a new main power control board goes in; should the error remain after that, the filter control board is next in line for replacement.
Cooktops in San Francisco showing 40 are handled by technician visit; see Kenmore cooktop repair or ring (415) 825-6393. It helps to have the model number to hand and to say whether the code appears every time the cooktop is switched on.
Model compatibility: Kenmore reuses codes across series and model years, so 40 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
Communication error between the main power control board and the filter control board.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your Kenmore appliance?
Book a specialist visit for a clear estimate and approval before any repair.
You submit a request with your appliance model and symptom, we confirm an appointment window, and a technician performs an on-site diagnosis. You then receive a clear estimate and decide whether to proceed before any repair begins.
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Replacement parts are selected for the exact model and confirmed with you before ordering or installation.
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