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Error code reference

Dacor Oven Error Code C73

Comm error

Dacor codesDacor oven codes

Comm error - incorrect board configuration detected (only one power board on double oven, two uppers/lowers connected, or upper/lower switches in wrong state).

First step from the service manual

Verify communication line connections and board ID switch settings. Correct wiring and switch state issues, then replace relay board if needed, lastly replace logic board.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What C73 means on a Dacor oven

The C73 error code on a Dacor oven indicates a communication fault caused by an incorrect board configuration being detected within the oven's control system. This code is specific to double oven installations and involves the relay (power) board and logic board communication architecture. The system expects a precise configuration: one power board paired correctly with upper and lower relay boards, each identified by their board ID switches. When the system detects only one power board on a double oven, finds two upper boards or two lower boards connected simultaneously, or detects that the upper/lower identification switches are set to the wrong state, it triggers the C73 fault.

The root cause is almost always a configuration issue rather than a hardware failure. The board ID switches physically tell each relay board whether it is serving the upper or lower oven cavity. If these switches are incorrectly set, swapped during a prior repair, or if wiring connections between boards are routed incorrectly, the logic board receives conflicting or unexpected identification signals during its communication handshake. This mismatch causes the logic board to halt normal operation and display C73.

Diagnosis begins with inspecting all communication line connections between the logic board and relay boards for loose, corroded, or improperly seated connectors. The board ID switch settings on each relay board must then be verified against the correct upper and lower designations for the specific installation. If wiring and switch states are confirmed correct and the fault persists, the relay board is the next component to replace. The logic board is considered a last resort if replacing the relay board does not resolve the fault.

Source: manufacturer service documentation.

Common causes of C73

  1. 01

    Incorrect board ID switch settings

    Wiring / connection

    Each relay board has physical switches that identify it as the upper or lower oven board. If these switches are set to the same position on both boards, or are otherwise incorrect, the logic board cannot distinguish between them and triggers C73.

  2. 02

    Two upper or two lower relay boards installed

    Part replacement

    If the wrong board type was installed during a prior repair, the system will detect duplicate upper or lower identifiers. Verify that one relay board is designated upper and one is designated lower.

  3. 03

    Loose or faulty communication line connections

    Wiring / connection

    Connectors linking the relay boards to the logic board can loosen over time or during servicing. Inspect all communication harness connections for secure seating, corrosion, or damaged pins.

  4. 04

    Only one power board present on a double oven

    Part replacement

    A double oven configuration requires the correct number of relay boards. If a board is missing due to a prior incomplete repair or shipping error, the logic board detects the gap in configuration and faults with C73.

  5. 05

    Failed relay board

    Part replacement

    If wiring and switch settings are all confirmed correct, a faulty relay board that is not communicating properly can still trigger this configuration error. Replacing the relay board is the next step after ruling out wiring and switch issues.

See the test procedure for each cause

Frequently asked questions about C73

What does C73 mean on a Dacor oven?
C73 on a Dacor oven signals a communication error caused by an incorrect board configuration. The system has detected a problem such as only one power board on a double oven, two upper or two lower relay boards connected at the same time, or board ID switches set to the wrong state. It is a control system configuration fault that typically appears after installation or a board replacement.
Can I fix a C73 error myself, or do I need a technician?
If you are comfortable working with appliance control boards and wiring harnesses, you can start by checking the communication line connections and verifying the board ID switch settings, which requires no parts. However, if the issue involves a missing, mismatched, or failed relay board, a technician will be better equipped to safely identify and replace the correct component.
Will resetting the oven clear the C73 error code?
A power reset may temporarily clear the display, but the C73 code will return if the underlying configuration problem is not corrected. The fault is tied to how the boards are wired and identified, so it will reappear on the next communication cycle until the switch settings, wiring, or faulty board are properly addressed.
Is it safe to use my Dacor oven while it shows a C73 error?
A C73 error indicates the control system cannot properly identify or communicate with the relay boards, which means the oven may not operate correctly or reliably. It is best to avoid using the oven until the configuration fault is resolved, as the system may not respond to commands as expected.
How much does it cost to repair a C73 error on a Dacor oven?
If the fix is simply correcting board ID switch settings or reseating a loose connector, there may be little to no parts cost, though a service call fee will apply if a technician is involved. If a relay board needs replacement, total repair costs including parts and labor typically range from around $200 to $500 or more depending on the specific board and local labor rates. Replacing the logic board, if needed as a last resort, will generally be on the higher end of that range.

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