Dacor Range, Oven, Cooktop Error Code U42

U42 indicates a failure detected on the relay board for the upper or single oven cavity. The relay board is responsible for switching power to the oven's heating elements and related components. When this board malfunctions or the control system cannot communicate with it properly, the U42 code is generated. The oven will typically be unable to heat until the fault is resolved.

You should not attempt to use the oven while U42 is displayed. A relay board failure can mean heating elements are not being controlled correctly, which could result in no heat, continuous heat, or unpredictable oven behavior. Discontinue use until the relay board has been inspected and the fault resolved.

Resetting the oven by disconnecting it from power for several minutes may temporarily clear the U42 code, but if the relay board has a genuine hardware failure, the error will return once the appliance is powered back up and the control system runs its diagnostics. A reset is useful for ruling out a transient fault, but it is not a substitute for proper diagnosis and repair.

Some basic checks, such as inspecting the wiring harness connectors for secure seating or resetting the appliance, can be performed by a careful DIYer. However, replacing the relay board involves working with line-voltage components and internal wiring, which carries a risk of serious injury if not handled correctly. It is strongly recommended to have a qualified appliance technician perform the diagnosis and repair.

Repair costs vary depending on whether the issue is a wiring connection or a full relay board replacement. A relay board for a Dacor oven can range from roughly $150 to $400 or more for the part alone, with labor adding $100 to $200 depending on your location and the technician. If only a wiring harness repair is needed, costs will be lower.