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Error code reference

Dacor Oven Error Code C72

TWI communication error

Dacor codesDacor oven codes

TWI communication error - no communication between logic and relay boards for at least 6 seconds.

First step from the service manual

Verify communication line connections (J7-J23, J8-J23) between relay and logic boards are solidly connected. If continuous resets/reboots, 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 C72 means on a Dacor oven

The C72 error code on a Dacor oven indicates a TWI (Two-Wire Interface) communication failure between the logic board and the relay board. TWI is a serial communication protocol used for internal data exchange between control boards. When the logic board loses contact with the relay board for a continuous period of at least 6 seconds, the oven triggers this fault code and halts normal operation. The communication link between these two boards travels through specific connectors identified as J7-J23 and J8-J23.

The relay board is responsible for switching high-voltage circuits on and off, including the bake and broil elements, while the logic board serves as the main controller that sends commands and monitors the oven's status. If the communication line between them is interrupted, the logic board cannot confirm that relay switching operations are occurring correctly, and the oven enters a fault state as a safety measure.

The most common trigger for C72 is a loose or partially disconnected wiring harness at one of the communication connectors. Vibration during operation, installation movement, or age-related connector fatigue can all cause the connection to degrade over time. If the connections at J7-J23 and J8-J23 are confirmed solid and the error persists or the oven is cycling through continuous resets and reboots, the logic board itself is the likely failed component and will need replacement.

Source: manufacturer service documentation.

Common causes of C72

  1. 01

    Loose or disconnected communication harness connectors

    Wiring / connection

    The connectors at J7-J23 and J8-J23 linking the relay and logic boards may have worked loose over time. Visually inspecting and firmly reseating these connectors is the first required diagnostic step.

  2. 02

    Damaged or corroded connector pins

    Wiring / connection

    Even if the harness appears connected, individual pins at the J7-J23 or J8-J23 connectors may be bent, corroded, or making intermittent contact. Inspect each pin carefully for physical damage or oxidation.

  3. 03

    Faulty communication wiring harness

    Part replacement

    The wiring harness running between the relay board and logic board may have a break, short, or damaged insulation that interrupts the TWI signal. A continuity check along the harness can confirm if the wiring itself has failed.

  4. 04

    Failed logic board

    Part replacement

    If connections are secure and the oven continues to display C72 or is cycling through continuous resets and reboots, the logic board is likely defective and no longer able to maintain TWI communication. Replacement of the logic board is the recommended next step.

  5. 05

    Failed relay board

    Part replacement

    A relay board with internal damage may fail to respond to TWI communication signals from the logic board. If logic board replacement does not resolve the fault, the relay board should also be evaluated as a potential source of the communication failure.

See the test procedure for each cause

Frequently asked questions about C72

What does C72 mean on a Dacor oven?
C72 indicates a TWI communication error, meaning the logic board and relay board have lost contact with each other for at least 6 seconds. These two boards exchange data continuously to control oven functions like heating element switching. When that communication link fails, the oven triggers this fault and stops operating as a safety precaution. The fault is rooted in the communication wiring between connectors J7-J23 and J8-J23.
Can I fix C72 on my Dacor oven myself?
A knowledgeable DIYer can attempt the first diagnostic step, which involves locating the communication connectors J7-J23 and J8-J23 between the relay and logic boards and firmly reseating them. If the error clears after reconnecting the harness, no further repair may be needed. However, if the oven continues to reset repeatedly or the error returns, replacing the logic board involves working near high-voltage components and is best handled by a qualified technician.
Is it safe to use my Dacor oven when C72 is displayed?
No, you should not attempt to operate the oven while C72 is active. The error indicates the control boards cannot communicate, which means the oven cannot properly manage its heating circuits. Operating an oven in this fault state could result in uncontrolled heating or other unpredictable behavior. Discontinue use until the fault is diagnosed and resolved.
Will resetting my Dacor oven clear the C72 error?
A power reset by turning off the circuit breaker for 30 to 60 seconds may temporarily clear the error if the communication disruption was a one-time event. However, if the underlying cause is a loose connector, damaged harness, or failing control board, the C72 code will return. Continuous resets or rebooting behavior after a reset is a strong indicator that the logic board needs to be replaced.
How much does it cost to repair a C72 error on a Dacor oven?
Repair costs vary depending on the root cause. If the issue is simply a loose connector, a service call fee of roughly $75 to $150 may be the only cost. If the logic board needs replacement, parts and labor combined typically range from $300 to $600 or more depending on the specific model and local labor rates. Getting a diagnostic estimate from a qualified technician before authorizing repairs is recommended.

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