Dacor Oven Error Code L31

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.

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.

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.

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.

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.