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Error code reference

Dacor Range Oven Cooktop Error Code U31

Temp sensor (upper/single oven)

Dacor codesDacor range oven cooktop codes

Temp sensor (upper/single oven) - shorted RTD 1, check wiring at connection points.

First step from the service manual

Check wiring at connection points.

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

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What U31 means on a Dacor range oven cooktop

Error code U31 on a Dacor range or oven indicates a shorted RTD (Resistance Temperature Detector) condition on the upper or single oven temperature sensor, designated RTD 1. An RTD sensor operates by changing its electrical resistance in proportion to temperature. Under normal operating conditions, the sensor produces a predictable resistance value that the control board reads to determine oven cavity temperature. When the RTD shorts internally or through its wiring harness, resistance drops abnormally low or falls to near zero, causing the control board to read a temperature that is implausibly high or erratic. The board interprets this as a fault and triggers U31 to halt operation and prevent potential overheating.

The most common sources of this fault are wiring problems rather than complete sensor failure. Pinched wires, melted insulation from proximity to oven heat, or corroded connector terminals can all create a short circuit in the sensor circuit. The diagnostic process begins at the connection points along the sensor wiring harness, checking for visible damage, loose pins, or moisture intrusion at connectors between the RTD sensor and the oven control board. Resistance testing of the sensor itself is the next step if wiring checks out clean.

If the wiring harness and connectors appear intact, the RTD sensor probe itself may have failed internally. A shorted RTD will typically read near zero ohms rather than the expected resistance value at room temperature. Replacing the sensor is straightforward in most Dacor oven configurations, as the probe is usually accessible from inside the oven cavity and secured with one or two mounting screws.

Source: manufacturer service documentation.

Common causes of U31

  1. 01

    Damaged or pinched sensor wiring harness

    Part replacement

    Heat exposure inside the oven cavity can melt or harden wire insulation, causing two conductors to contact each other and create a short. Inspect the full length of the wiring harness from the sensor probe to the control board connection for any visible damage.

  2. 02

    Corroded or loose wiring connector

    Wiring / connection

    The connector terminals between the RTD sensor and the control board can corrode or back out of their housing, causing intermittent or sustained short circuit conditions. Check each connection point for oxidation, bent pins, or poor seating.

  3. 03

    Failed RTD temperature sensor (internal short)

    Part replacement

    The RTD probe itself can fail internally, producing a near-zero resistance reading that the control board registers as a short. Testing the sensor with a multimeter at room temperature will reveal an abnormally low or zero ohm reading if the probe has shorted internally.

  4. 04

    Moisture or grease contamination at connector

    Wiring / connection

    Moisture or grease that has migrated into the wiring connector can bridge the sensor terminals and cause a short circuit reading. Cleaning and drying the connector thoroughly may resolve the fault if no physical damage is present.

  5. 05

    Faulty oven control board

    Part replacement

    If the sensor and all wiring check out correctly with a multimeter and no damage is found, the control board's sensor input circuit may have failed and is falsely reporting a short condition. This is the least common cause and should be diagnosed only after all other components are confirmed good.

See the test procedure for each cause

Frequently asked questions about U31

What does U31 mean on a Dacor range, oven, cooktop?
U31 indicates a shorted RTD 1 condition, meaning the upper or single oven temperature sensor circuit is reading an abnormally low resistance that the control board interprets as a short circuit. The sensor, designated RTD 1, is the primary temperature probe for the oven cavity. The control board disables normal operation when this fault is detected to prevent uncontrolled heating. The fault points to either a wiring problem in the sensor circuit or a failed sensor probe.
Can I fix a U31 error on my Dacor oven myself?
A knowledgeable DIYer can address this fault by starting with a visual inspection of the sensor wiring harness and connector points, which are the most likely cause. If the wiring looks intact, testing the RTD sensor with a multimeter to check its resistance is a straightforward next step. Replacing the sensor probe is generally accessible from inside the oven cavity. However, if the fault traces back to the control board, professional repair is recommended.
Is it safe to use my Dacor oven while it shows the U31 error?
You should not attempt to use the oven while U31 is active. A shorted temperature sensor means the control board cannot accurately monitor the oven cavity temperature, which removes a critical safety safeguard against overheating. Operating the oven in this condition is not recommended until the sensor circuit has been repaired and verified.
How much does it cost to repair a U31 error on a Dacor oven?
If only the RTD temperature sensor needs replacement, parts and labor typically run in the range of $100 to $250 depending on the specific model and local labor rates. If the wiring harness requires repair or replacement, costs can vary widely based on the extent of the damage. A control board replacement, if needed, is generally the most expensive outcome and can range from $300 to $600 or more including installation.
Will resetting my Dacor oven clear the U31 error code?
A power reset, such as switching off the circuit breaker for 60 seconds, may temporarily clear the U31 code, but it will return if the underlying fault in the sensor circuit is not repaired. Because U31 reflects an actual measured electrical condition (a short in the RTD circuit), the error will reappear once the control board runs its diagnostics again. A reset alone is not a fix and the sensor wiring and probe should be inspected before returning the oven to service.

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