mypros+
Error code reference

Dacor Oven Error Code U30

Upper/single oven temp sensor open probe 1

Dacor codesDacor oven codes

Upper/single oven temp sensor open probe 1 - 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. Secure connection, replace probe, or replace harness.

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 U30.

  • 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 U30 means on a Dacor oven

The U30 error code on a Dacor oven indicates that the upper or single oven temperature sensor (probe 1) has developed an open circuit condition. The control system continuously monitors the analog-to-digital (A/D) conversion value from the temperature probe. When that value reaches 0X3F0 or higher and remains at that level for 60 or more continuous seconds, the control interprets this as a broken or disconnected sensor circuit and triggers the U30 fault. An open probe condition means the sensor circuit is no longer completing a valid resistance path back to the control board, causing the A/D reading to peg at its upper limit.

The temperature sensor in Dacor ovens is a resistance-based probe, typically a negative temperature coefficient (NTC) or positive temperature coefficient (PTC) type device. Under normal operation, the sensor changes resistance in a predictable way as oven temperature rises and falls, and the relay board converts that resistance into a voltage signal read by the A/D converter. When the probe itself fails internally, when its wiring harness breaks or corrodes, or when a connector separates at the relay board or at the probe itself, the circuit goes open and the A/D value climbs to an out-of-range reading.

Diagnosis begins at the relay board by inspecting the probe connector for loose, corroded, or backed-out terminals. The probe should also be checked at its own connector for continuity and correct resistance at room temperature. If connections are secure and the resistance reading is out of specification or infinite, the probe itself has failed and needs replacement. A damaged wiring harness between the probe and the relay board is another possible cause and should be inspected for pinched, burned, or broken wires.

Source: manufacturer service documentation.

Common causes of U30

  1. 01

    Failed temperature probe

    Part replacement

    The probe itself has developed an internal open circuit, meaning its resistance is no longer measurable. Checking the probe with a multimeter at the connector will show infinite or no resistance reading.

  2. 02

    Loose or disconnected probe connector

    Wiring / connection

    The connector at the probe or at the relay board has worked loose, interrupting the circuit. Visually inspect both ends of the probe wiring and reseat any connectors that are not fully engaged.

  3. 03

    Damaged wiring harness

    Part replacement

    The harness running between the temperature probe and the relay board may have a broken wire, burned insulation, or a pinched section caused by oven components shifting during use. A continuity test on each wire in the harness will identify the break.

  4. 04

    Corroded or burnt connector terminals

    Part replacement

    High oven temperatures can degrade connector terminals over time, creating resistance or a fully open connection at the relay board or probe connector. Inspect terminals for discoloration, oxidation, or melting.

  5. 05

    Relay board fault

    Part replacement

    If the probe and harness both test correctly and connections are secure, the relay board's sensor input circuit may have failed. This is the least likely cause and should be diagnosed only after the probe and harness are confirmed good.

See the test procedure for each cause

Frequently asked questions about U30

What does U30 mean on a Dacor oven?
U30 indicates that the upper or single oven temperature sensor probe 1 has an open circuit. The oven's control system detected an out-of-range A/D value of 0X3F0 or higher for at least 60 continuous seconds, which signals that the sensor circuit is broken or disconnected. The oven cannot regulate temperature safely while this fault is active.
Will resetting my Dacor oven clear the U30 error?
Resetting the oven by cutting power at the breaker may temporarily clear the display, but the fault will return as soon as the control re-reads the sensor and detects the open circuit condition again. A lasting fix requires repairing or replacing the defective component, whether that is the probe, the harness, or a connector.
Is it safe to use my Dacor oven while U30 is displayed?
No, it is not safe to operate the oven with an active U30 fault. Without a functioning temperature sensor, the control board cannot monitor or regulate oven temperature, which creates a risk of overheating. The oven should remain off until the sensor circuit is repaired.
How do I fix the U30 error on a Dacor oven?
Start by inspecting the wiring connectors at the relay board and at the temperature probe itself, reseating any that are loose. If connections are secure, test the probe with a multimeter for continuity and correct resistance. A probe showing infinite resistance has failed and needs to be replaced. If the probe tests fine, inspect the wiring harness for damage and replace it if a broken wire is found.
How much does it cost to repair a U30 error on a Dacor oven?
Repair costs depend on which component has failed. A replacement temperature probe typically ranges from $30 to $80 for the part. A wiring harness can range from $20 to $60 depending on the specific model. If professional labor is involved, expect to add $100 to $200 or more for the service call and diagnostic time. Relay board replacement, if required, is significantly more expensive.

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