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Error code reference

U-Line Ice Maker Error Code E2

Thermistor 2 (Condenser/Liquid Line thermistor) is open circuit.

U-Line codesU-Line ice maker codes

Thermistor 2 (Condenser/Liquid Line thermistor) is open circuit.

First step from the service manual

Check thermistor 2 connections are clean and dry; measure resistance with ohmmeter.

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

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What E2 means on a U-Line ice maker

The E2 error code on a U-Line ice maker indicates that Thermistor 2, the condenser or liquid line thermistor, has been detected as an open circuit. An open circuit condition means the thermistor is no longer completing the electrical loop required for resistance measurement. The control board sends a reference voltage through the thermistor and monitors the return signal to calculate temperature. When the circuit is broken, the board receives no valid signal and triggers E2 to prevent the unit from operating with missing thermal data.

Thermistor 2 is positioned to monitor condenser or liquid line temperatures, which are critical for regulating refrigerant flow and compressor operation. Without accurate readings from this sensor, the ice maker cannot properly manage its refrigeration cycle. The thermistor itself is a negative temperature coefficient (NTC) resistive device, meaning its resistance decreases as temperature rises. An open circuit typically reads as infinite or unmeasurable resistance on an ohmmeter, which is outside the normal operating range for an NTC thermistor.

The most common causes of an open circuit thermistor include a broken or corroded wiring harness, a failed thermistor probe, or a loose connector at either the thermistor or the control board. Physical damage from ice buildup, moisture intrusion at connector points, or simple component fatigue over time can all break the circuit. Start diagnosis by inspecting the thermistor 2 wiring harness and connectors for corrosion, moisture, or physical damage, then measure resistance across the thermistor terminals with an ohmmeter to confirm whether the fault is in the sensor itself or the wiring.

Source: manufacturer service documentation.

Common causes of E2

  1. 01

    Broken or damaged wiring harness

    Wiring / connection

    Physical damage to the wires connecting Thermistor 2 to the control board is a leading cause of open circuit faults. Inspect the full length of the harness for cuts, pinches, or breaks, especially near routing clips or sharp edges.

  2. 02

    Corroded or loose connector

    Wiring / connection

    Moisture or ice exposure can corrode the connector pins at the thermistor or at the control board, breaking the circuit without visibly damaging the wire. Check that all connectors are fully seated and that pins are clean and free of oxidation.

  3. 03

    Failed thermistor probe

    Part replacement

    The thermistor itself can fail internally, resulting in an open circuit even when wiring and connectors appear intact. Confirm this by measuring resistance across the thermistor terminals with an ohmmeter; an open circuit reading (infinite resistance) indicates a defective probe that requires replacement.

  4. 04

    Moisture intrusion at connector

    Wiring / connection

    Water or ice melt entering the thermistor connector can cause intermittent or permanent open circuit conditions. Connectors should be inspected for moisture, dried thoroughly, and checked for any signs of water damage to the pins or housing.

  5. 05

    Control board fault

    Part replacement

    If the thermistor and all associated wiring test correctly, the control board input circuit monitoring Thermistor 2 may have failed. This is the least common cause and should only be considered after ruling out the sensor and harness.

See the test procedure for each cause

Frequently asked questions about E2

What does E2 mean on a U-Line ice_maker?
E2 on a U-Line ice maker indicates that Thermistor 2, the condenser or liquid line thermistor, is reading as an open circuit. This means the control board cannot detect a valid resistance signal from that sensor. The unit will not operate normally until the fault is resolved. The cause is typically a broken wire, corroded connector, or failed thermistor probe.
Can I fix an E2 error on my U-Line ice maker myself?
Some parts of the diagnosis are DIY-friendly, such as inspecting connectors for corrosion, ensuring connections are clean and dry, and measuring thermistor resistance with an ohmmeter. If the thermistor probe itself has failed, replacing it requires disconnecting the wiring harness and accessing the condenser area, which is manageable for experienced DIYers. However, if the control board is suspect, professional service is recommended.
Will resetting my U-Line ice maker clear the E2 error?
A simple reset will not permanently clear the E2 error if the underlying open circuit condition still exists. The control board will re-detect the fault and display E2 again once it resumes monitoring. The thermistor circuit must be repaired or the faulty component replaced before the error will stay cleared.
Is it safe to continue using my U-Line ice maker while E2 is displayed?
Operating the ice maker while E2 is active is not recommended. Without valid temperature data from the condenser or liquid line thermistor, the control board cannot properly regulate the refrigeration cycle. Continued operation in this state could result in inefficient cooling, compressor stress, or further component damage.
How much does it cost to repair a U-Line ice maker showing an E2 error?
Repair costs depend on the root cause. If only a connector cleaning or wiring repair is needed, costs are generally low. Thermistor probe replacement typically falls in the range of $20 to $80 for the part, plus labor if a technician is involved. Control board replacement is significantly more expensive, often ranging from $150 to $400 or more for parts and labor combined.

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