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Error code reference

Dacor Range Oven Cooktop Error Code C34

Heritage: Relay board ambient temp probe open

Dacor codesDacor range oven cooktop codes

Heritage: Relay board ambient temp probe open - open thermistor detected.

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  • Step-by-step tests with expected resistance, voltage, and continuity values
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What C34 means on a Dacor range oven cooktop

The C34 error code on Dacor Heritage series ranges and ovens indicates that the relay board's ambient temperature probe has been detected as an open circuit. The ambient thermistor on the relay board monitors the temperature of the board's operating environment, providing feedback to protect the control electronics from overheating. When the control system reads an open circuit from this thermistor, it means the resistance value has gone outside the expected range in the direction of infinite or unmeasurably high resistance, which is the characteristic signature of a broken or disconnected thermistor circuit.

The most common root causes include a failed thermistor element itself, a wiring harness break between the thermistor and the relay board, or a corroded or disconnected connector at either end of the circuit. Thermistors are passive resistive components that change resistance predictably with temperature, and when they fail open, the control board can no longer receive a valid temperature reading, triggering the fault code as a protective measure.

The relay board itself is the central component involved, as the ambient probe is physically associated with it rather than the oven cavity. Diagnosing this fault requires inspecting the thermistor's resistance with a multimeter, checking wiring continuity between the probe and relay board, and examining connector integrity. If the thermistor reads open or infinite resistance at room temperature, replacement of the probe or the relay board assembly is necessary to clear the fault.

Source: manufacturer service documentation.

Common causes of C34

  1. 01

    Failed ambient thermistor

    Part replacement

    The thermistor element itself has failed open, producing infinite resistance instead of a normal temperature-dependent value. Measuring the thermistor with a multimeter at room temperature will show no continuity or infinite resistance, confirming failure.

  2. 02

    Broken or damaged wiring harness

    Part replacement

    A break in the wire between the ambient thermistor and the relay board creates an open circuit condition identical to a failed thermistor. Inspect the harness for pinching, heat damage, or visible wire breaks along its entire length.

  3. 03

    Loose or corroded connector

    Wiring / connection

    The connector at the thermistor or at the relay board input may have worked loose or corroded, interrupting the circuit. Disconnecting and inspecting both connectors for oxidation, bent pins, or a poor seat can identify this cause.

  4. 04

    Faulty relay board

    Part replacement

    If the thermistor and all wiring check out correctly, the relay board itself may have a damaged input circuit that incorrectly reads the probe as open. This is less common but requires relay board replacement if other components test good.

See the test procedure for each cause

Frequently asked questions about C34

What does C34 mean on a Dacor range, oven, cooktop?
C34 on a Dacor Heritage series appliance means the control system has detected an open circuit from the ambient temperature thermistor located on the relay board. This thermistor monitors the temperature of the relay board's environment to protect the electronics. An open thermistor means the sensor is reading infinite or unmeasurable resistance, which is outside the normal operating range. The oven triggers this code to prevent damage from operating without valid temperature feedback.
Can I fix the C34 error myself, or do I need a technician?
A knowledgeable DIYer can inspect the wiring harness and connectors for visible damage or loose connections without special tools. However, accurately testing the thermistor and relay board requires a multimeter and familiarity with reading resistance values. If parts need to be replaced, particularly the relay board, professional service is strongly recommended to ensure correct installation and safe operation.
Is it safe to use my Dacor oven while the C34 error is displayed?
Operating the oven with an active C34 fault is not recommended. The ambient thermistor protects the relay board from overheating, and without a functioning probe, the control system cannot detect a dangerous temperature rise in the electronics. Continued use could potentially cause further damage to the relay board or other components.
Will resetting the oven clear the C34 error code?
Performing a reset, such as cycling the circuit breaker or disconnecting power, may temporarily clear the code, but it will return if the underlying problem with the thermistor or wiring is not repaired. A reset does not fix the open circuit condition. The fault must be diagnosed and the defective component corrected before the error will stay cleared.
How much does it cost to repair a C34 error on a Dacor oven?
Repair costs vary depending on the root cause. Reconnecting a loose connector involves only a service call fee, typically in the range of $75 to $150. Replacing the ambient thermistor probe is a lower-cost part repair, while replacing the relay board is more expensive, with parts and labor often ranging from $300 to $600 or more depending on the specific model and technician rates in your area.

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