Electrolux Oven Error Code F21

F21 indicates a communication problem between the User Interface Board and the Appliance Control Board. The User Interface Board is no longer detecting communication signals from the Appliance Control Board. The fault points to the communication harness running from connector P20 on the Appliance Control Board to connector J2 on the User Interface Board as the first area to inspect.

It is not recommended to operate the oven while an F21 error is active. Because the two control boards cannot communicate, the oven may not respond correctly to user inputs or safety controls. You should avoid using the oven until the fault is diagnosed and resolved.

Repair costs vary depending on the root cause. If the issue is a loose connector or a replaceable harness, costs are typically lower, generally in the range of $50 to $150 for parts and labor. If the Appliance Control Board or User Interface Board requires replacement, costs can range from $150 to $400 or more depending on parts pricing and labor rates in your area.

Some causes of F21 are DIY-accessible, such as reseating loose connectors or inspecting the harness for visible damage. You should disconnect power to the oven before handling any internal connectors or wiring. If the harness and connectors appear intact, diagnosing whether the Appliance Control Board or User Interface Board has failed typically requires a multimeter and some familiarity with control board testing, so professional service may be appropriate at that stage.

Disconnecting power to the oven for several minutes and restoring it may temporarily clear the F21 code, but the error will return if the underlying communication fault is not corrected. A reset is useful for confirming whether the fault is intermittent, but it is not a repair. The harness and board connections should still be inspected.