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Error code reference

Dacor Oven Error Code L34

Lower oven temp sensor open probe 3

Dacor codesDacor oven codes

Lower oven temp sensor open probe 3 - A/D value of 0X3F0 or higher registered for 60 continuous seconds.

First step from the service manual

Verify connections at relay board. Verify probe state at probe connector.

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

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What L34 means on a Dacor oven

Error code L34 on a Dacor oven indicates that the lower oven temperature sensor (probe 3) is in an open-circuit condition. Specifically, the analog-to-digital converter monitoring that probe has registered a value of 0x3F0 or higher continuously for 60 seconds. An A/D value at or above this threshold corresponds to an extremely high resistance reading across the sensor circuit, which the control interprets as an open probe rather than a valid temperature signal. This is distinct from a shorted probe condition and points to a broken circuit somewhere between the relay board and the sensor itself.

The lower oven temp sensor is a negative temperature coefficient (NTC) or resistance-based probe that changes its resistance in proportion to oven cavity temperature. When the circuit is intact and the oven is at ambient temperature, the sensor presents a predictable resistance value. An open circuit, whether from a broken probe element, a disconnected harness, or a failed connector, sends the A/D reading to its upper rail, triggering this fault. The 60-second timer is built in to prevent nuisance trips from momentary electrical noise.

Diagnosis should begin at the relay board connections and at the probe connector itself, as directed by the first diagnostic step. A loose or corroded connector pin can break continuity without any visible wire damage. If connections check out, the probe itself should be tested for continuity and proper resistance at room temperature. A completely open probe will show infinite resistance on a multimeter and requires replacement.

Source: manufacturer service documentation.

Common causes of L34

  1. 01

    Loose or disconnected probe connector

    Wiring / connection

    A disconnected or poorly seated connector at the probe or at the relay board will immediately create an open circuit. Inspect both ends of the sensor harness and reseat any connectors that show signs of looseness or corrosion.

  2. 02

    Failed temperature sensor (open element)

    Part replacement

    The probe element itself can fail internally, breaking the circuit. Testing with a multimeter should show a finite resistance at room temperature; an infinite reading confirms the probe is open and must be replaced.

  3. 03

    Damaged sensor wiring harness

    Part replacement

    The wiring between the relay board and the probe connector can be pinched, burned, or broken, especially near high-heat areas inside the oven cavity. Visually inspect the harness for any breaks, melted insulation, or chafing.

  4. 04

    Corroded or burnt connector pins

    Wiring / connection

    Even if the connector is physically seated, individual pins can corrode or burn out, creating an open in the circuit. Check each pin at the relay board connector and the probe connector for discoloration, pitting, or buildup.

  5. 05

    Faulty relay board

    Part replacement

    If the sensor, wiring, and all connectors test correctly, the relay board input circuit for probe 3 may have failed. This is the least common cause but should be considered after all other components are ruled out.

See the test procedure for each cause

Frequently asked questions about L34

What does L34 mean on a Dacor oven?
L34 means the lower oven temperature sensor (probe 3) is reading an open circuit. The oven's control has detected an analog-to-digital value of 0x3F0 or higher on that sensor input for 60 consecutive seconds, which indicates the sensor circuit is not functioning. The fault could originate at the sensor itself, the wiring harness, or the connectors at the relay board.
Can I fix the L34 error myself?
A knowledgeable DIYer can perform the initial diagnostic steps, including checking and reseating connectors at the relay board and the probe connector. Testing the sensor with a multimeter for continuity and resistance is also within reach for someone comfortable working with appliances. However, if the relay board itself needs replacement, professional service is recommended to ensure correct installation.
Is it safe to use my Dacor oven while L34 is displayed?
You should not continue using the oven while this fault is active. With the lower oven temperature sensor in an open-circuit state, the control cannot accurately monitor heat in the lower cavity. Operating the oven without a functional temperature sensor creates a risk of overheating and uncontrolled temperatures.
Will resetting the oven clear the L34 error code?
A power reset may temporarily clear the fault display, but L34 will return if the underlying open-circuit condition is still present. Because the code requires the out-of-range A/D value to persist for 60 continuous seconds, the fault will reappear as soon as the oven attempts to use that sensor. A reset is not a repair and the root cause must be addressed.
How much does it cost to repair a Dacor oven L34 error?
Repair costs depend on the root cause. Reconnecting a loose connector costs nothing beyond the diagnostic time. A replacement lower oven temperature sensor typically runs in the range of $30 to $80 for parts. If the relay board requires replacement, parts alone can range from $150 to $350 or more, with additional labor costs if a technician is needed.

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