Kenmore Range Error Code F40

The F40 error code on a Kenmore range indicates a cooktop lockout failure. This code applies to select models equipped with a dedicated cooktop lockout board, which is a secondary control module responsible for enabling or disabling the surface burners based on commands from the main Electronic Oven Control (EOC). When the EOC cannot establish or maintain proper communication with the cooktop lockout board, it triggers the F40 fault to alert the technician to a breakdown in this control circuit.

The primary communication path between these two components runs through connector P10 on the EOC and connector P1 on the cooktop lockout board. A failure at any point along this harness, including loose terminals, corroded pins, or broken wires, can interrupt the signal and cause the F40 code to appear. The diagnostic process begins at these connectors before any components are replaced, since a simple connection issue is often the root cause.

If the wiring harness checks out with confirmed continuity and the connections are secure, the cooktop lockout board itself is the next suspect. This board can fail internally due to component degradation or electrical stress. If replacing the lockout board does not resolve the fault, the EOC may be at fault, as it is responsible for initiating the communication signal. Replacing the EOC is the final step when all other diagnostics have been exhausted.