Dacor Range Oven Cooktop Error Code U34

The U34 error code on a Dacor range or oven indicates an open circuit condition in RTD 3, which is the resistance temperature detector assigned to the upper or single oven cavity. RTDs are precision temperature-sensing resistors whose resistance changes predictably with temperature. An "open" RTD means the circuit has been broken entirely, producing infinite or unmeasurable resistance. The oven control board receives no valid temperature data and triggers U34 to prevent the oven from operating in an uncontrolled thermal state.

The most likely origin of the fault is at the wiring connection points between the RTD sensor and the control board. Connectors in oven environments are exposed to repeated heat cycling, which can cause terminals to oxidize, corrode, or pull back from their pins over time. A loose or corroded connector can mimic a failed sensor even when the sensor itself is intact. Because the error code description specifically calls out wiring at connection points as the first diagnostic step, inspecting and reseating all connectors in the RTD 3 circuit should be completed before any components are replaced.

If wiring and connectors are confirmed to be in good condition, the RTD sensor itself may have failed internally. An open RTD will show no continuity when tested with a multimeter across its terminals. Additionally, any break or chafing in the wire harness between the sensor and the board can produce the same open-circuit reading. The control board is rarely the root cause but should be considered if the sensor and wiring both test good.