mypros+
Error code reference

Dacor Oven Error Code L31

Lower oven temp sensor shorted probe 1

Dacor codesDacor oven codes

Lower oven temp sensor shorted probe 1 - A/D value of 0X0010 or lower 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.

MyPros+ Max

Get the full diagnostic procedure for L31.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What L31 means on a Dacor oven

The L31 error code on a Dacor oven indicates that the lower oven temperature sensor probe 1 has developed a short circuit condition. Specifically, the analog-to-digital converter on the control system has registered a value of 0x0010 or lower continuously for 60 seconds. This threshold represents an extremely low resistance reading at the sensor input, which the control interprets as a shorted probe rather than a valid temperature signal. Under normal operating conditions, the temperature sensor (typically an RTD or thermistor-type probe) produces a resistance value that changes predictably with temperature, and the A/D converter translates that into a usable temperature reading.

A shorted probe condition means the sensor's resistance has collapsed to near zero, causing the A/D value to fall below the minimum valid range. This can result from a failed sensor probe internally shorting its resistance element, damaged wiring with conductors making direct contact, or a compromised connector at either the probe end or the relay board. The 60-second continuous duration requirement prevents nuisance faults from brief transient events, so when L31 triggers, the short is persistent rather than momentary.

The first diagnostic steps focus on the relay board connections and the probe connector itself. Loose or corroded connections at the relay board can introduce false low-resistance readings, and a visual and resistance check at the probe connector will quickly confirm whether the sensor element itself has failed or whether the fault lies in the wiring and connector path. Disconnecting the probe and measuring its resistance at room temperature can isolate whether the sensor or the circuit is at fault.

Source: manufacturer service documentation.

Common causes of L31

  1. 01

    Failed lower oven temperature sensor probe

    Part replacement

    The internal resistance element inside the probe can short out due to heat stress or physical damage, causing resistance to drop near zero. Measuring resistance across the probe terminals while disconnected will confirm a shorted element, typically showing near-zero ohms instead of the expected value.

  2. 02

    Damaged or pinched sensor wiring

    Part replacement

    Wiring routed near high-heat areas or caught under oven components can have its insulation burned through, allowing conductors to contact each other or the oven chassis. Inspect the full length of the sensor wiring harness for visible burn marks, pinch points, or bare wire.

  3. 03

    Loose or corroded connection at the relay board

    Wiring / connection

    A poor connection at the relay board terminal can produce erratic or falsely low resistance readings at the A/D input. Reseating the connector firmly and inspecting terminals for corrosion or pushed-back pins is the recommended first check.

  4. 04

    Faulty probe connector at the sensor end

    Wiring / connection

    The connector at the probe itself can develop corrosion, loose pins, or a short between adjacent terminals, particularly in the high-temperature lower oven environment. Inspect the connector body and terminals for heat damage, debris bridging contacts, or corrosion.

  5. 05

    Relay board analog input failure

    Part replacement

    If the sensor probe and all wiring check out correctly at normal resistance values, the A/D input circuit on the relay board itself may have failed and is falsely reporting a low value. This is less common but should be considered after all wiring and sensor checks are complete.

See the test procedure for each cause

Frequently asked questions about L31

What does L31 mean on a Dacor oven?
L31 means the lower oven temperature sensor probe 1 has been detected in a shorted condition. The control system's analog-to-digital converter registered a value of 0x0010 or lower for 60 continuous seconds, indicating the sensor's resistance has collapsed below the valid operating range. This is a persistent fault rather than a momentary glitch, and the oven will require inspection of the sensor, wiring, and relay board connections before it can operate normally.
Can I reset the L31 code to get my Dacor oven working again?
Resetting the oven by cutting power may temporarily clear the L31 display, but the code will return if the underlying short circuit condition is still present. Because the fault must persist for 60 continuous seconds before triggering, it is not a nuisance error that clears itself with a simple reset. The probe, wiring, and connectors need to be diagnosed and the root cause corrected for the error to stay cleared.
Is it safe to use my Dacor oven while the L31 code is active?
It is not advisable to operate the oven with an active L31 fault. The lower oven temperature sensor is the primary feedback mechanism the control board uses to regulate heat in the lower cavity. With a shorted sensor providing invalid data, the oven cannot accurately control temperature, which presents a risk of overheating or unpredictable cooking performance. The fault should be repaired before resuming use.
How much does it cost to fix a Dacor oven L31 error?
Repair costs vary depending on the root cause. Replacing a lower oven temperature sensor probe typically runs between $50 and $150 for the part, plus labor if a technician is performing the repair. If the wiring harness requires replacement, costs can be higher. In the less common scenario where the relay board's A/D input has failed and the board needs replacement, costs can range from $150 to $400 or more for the board alone. Diagnosing the fault first before purchasing parts is strongly recommended.
How do I diagnose whether the sensor or the wiring is causing the L31 code on my Dacor oven?
Start by disconnecting the sensor probe at its connector and measuring resistance across the probe terminals with a multimeter. A shorted probe will show near-zero ohms rather than the expected resistance value for the sensor type. If the probe reads correctly in isolation, inspect the wiring harness from the probe to the relay board for damage, pinching, or burned insulation, and check the connector at the relay board for loose, corroded, or bridged terminals. This process isolates whether the fault is in the sensor itself, the wiring, or the board-side connection.

Related Dacor oven codes

All Dacor oven codes
View all 71 Dacor oven codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass