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Error code reference

Dacor Oven Error Code U33

Upper/single oven temp sensor shorted probe 2

Dacor codesDacor oven codes

Upper/single oven temp sensor shorted probe 2 - 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. Secure connection, replace probe, or replace harness.

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

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What U33 means on a Dacor oven

The U33 error code on a Dacor oven indicates that the upper or single oven temperature sensor (probe 2) has developed a short circuit condition. Specifically, the oven's control system has detected an analog-to-digital (A/D) conversion value of 0x0010 or lower held continuously for 60 seconds or more. This extremely low A/D value signals that the sensor circuit is returning a near-zero resistance reading, which is the electrical signature of a shorted probe rather than a properly functioning thermistor that would vary resistance with temperature.

The temperature probe in a Dacor oven is a resistive sensor whose resistance changes predictably as oven cavity temperature rises and falls. The relay board reads this resistance through an A/D converter to determine the actual oven temperature. When the probe shorts internally or the wiring harness creates an unintended low-resistance path to ground, the A/D reading collapses to the threshold value that triggers U33. This is distinct from an open-circuit fault, where resistance would read extremely high. A short drives the reading in the opposite direction toward zero.

Diagnosis begins at the relay board by confirming that all connectors seating the probe harness are fully engaged and free of corrosion or damage. From there, the probe itself should be tested at the probe connector to determine whether the short originates in the sensor element or in the wiring harness routing between the probe and relay board. Depending on findings, the resolution involves securing a loose connection, replacing the temperature probe, or replacing the harness if insulation damage has caused the conductors to contact each other or a grounded surface.

Source: manufacturer service documentation.

Common causes of U33

  1. 01

    Failed temperature probe (internal short)

    Part replacement

    The probe element itself can short internally when the sensor's resistive wire contacts the probe sheath due to physical damage, moisture intrusion, or heat-related degradation. Testing resistance across the probe terminals will show a near-zero reading rather than the expected thermistor value.

  2. 02

    Damaged wiring harness

    Part replacement

    High heat exposure inside the oven cavity can melt or crack harness insulation, causing the two probe conductors to touch each other or contact a grounded metal surface. Visually inspect the full harness run for pinched, melted, or abraded sections.

  3. 03

    Loose or corroded connector at relay board

    Wiring / connection

    A poorly seated or corroded connector at the relay board can create resistance anomalies that mimic a shorted probe. Disconnecting and firmly reseating the probe harness connector at the relay board is the first step before replacing any components.

  4. 04

    Loose connection at probe connector

    Wiring / connection

    The connector at the probe end of the harness can back out or corrode, particularly near the oven cavity where thermal cycling is severe. Inspect and reseat this connector as part of the initial verification process.

  5. 05

    Relay board fault

    Part replacement

    If the probe and harness both test within normal parameters, the A/D input circuit on the relay board itself may have failed, causing it to register false low readings. Board replacement would be the corrective action after all other causes are ruled out.

See the test procedure for each cause

Frequently asked questions about U33

What does U33 mean on a Dacor oven?
U33 means the upper or single oven temperature sensor (probe 2) has been detected in a shorted condition. The oven's control system measures an analog-to-digital value of 0x0010 or lower from the sensor circuit, and when that low reading persists for 60 continuous seconds, the U33 code is triggered. A shorted probe returns a near-zero resistance reading, which prevents the oven from accurately monitoring cavity temperature. The fault can originate in the probe itself, the wiring harness, or a connector.
Can I fix U33 myself, or do I need a technician?
A knowledgeable DIYer can start by checking and reseating the probe harness connectors at both the relay board and the probe end, since a loose connection is a possible cause. If reconnecting does not clear the code, testing the probe's resistance with a multimeter will confirm whether the sensor has shorted internally. Probe replacement is a manageable DIY repair, but if the fault points to the relay board or a harness routed deep within the oven cavity, professional service is recommended.
Is it safe to use my Dacor oven while U33 is displayed?
No, you should not continue using the oven with U33 active. A shorted temperature sensor means the control system cannot reliably read the oven cavity temperature, which can result in uncontrolled heating or incorrect cycle behavior. Continued operation under these conditions risks damage to the oven and could present a safety hazard. Resolve the fault before resuming normal use.
Will resetting the oven clear the U33 error code?
A power reset may temporarily clear the display, but the code will return within 60 seconds of startup if the underlying short circuit is still present. Because the fault requires the low A/D reading to persist for a full minute before triggering, a reset only delays the reappearance. The probe, harness, and connectors must be inspected and repaired before the error will stay cleared.
How much does it cost to repair a U33 error on a Dacor oven?
Repair cost depends on which component is at fault. A replacement temperature probe typically runs in the range of $30 to $80 for the part, while a wiring harness can range from $40 to $120 depending on the model. If the relay board requires replacement, parts alone can range from $150 to $400 or more. Adding professional labor, total repair costs generally fall between $100 and $500 depending on the diagnosis outcome and service rates in your area.

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