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Error code reference

U-Line Refrigerator Error Code No Comm

Unit lost communication between the main control board and the display.

U-Line codesU-Line refrigerator codes

Unit lost communication between the main control board and the display.

First step from the service manual

Disconnect and reconnect power to unit. Contact Customer Care if persistent.

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What No Comm means on a U-Line refrigerator

The No Comm error on a U-Line refrigerator indicates a loss of communication between the main control board and the user interface display board. These two components rely on a continuous data signal to share operational information, including temperature readings, mode settings, and system status. When this signal is interrupted or fails to establish properly, the unit flags the No Comm fault to alert the user or technician that the control system is not functioning as an integrated unit.

The most common trigger for this error is a temporary disruption in the communication pathway, which can result from a power fluctuation, a brief voltage sag, or a momentary firmware lockup on either board. Because of this, a power cycle is the recommended first diagnostic step. Disconnecting the unit from power, waiting at least one to two minutes to allow capacitors to discharge and firmware to reset, and then restoring power will often clear the fault without any further intervention.

If the error returns after a power cycle, the issue is more likely rooted in a hardware fault. The wiring harness connecting the main control board to the display board should be inspected for loose connectors, corrosion, or physical damage. A failed main control board or a defective display board can also prevent the communication signal from being established or maintained, requiring component-level diagnosis and potential board replacement.

Source: manufacturer service documentation.

Common causes of No Comm

  1. 01

    Temporary firmware or power disruption

    Wiring / connection

    A brief power fluctuation or firmware lockup on either board can interrupt the communication signal. A power cycle resolves this in many cases without any parts replacement.

  2. 02

    Loose or disconnected wiring harness

    Wiring / connection

    The connector linking the main control board to the display board can work loose over time due to vibration or handling. Inspecting and reseating the harness connectors may restore communication.

  3. 03

    Corroded or damaged wiring connector

    Part replacement

    Moisture or age can cause corrosion at the connector pins between the display and main board, degrading the signal. Visible corrosion or damaged pins at the connector will typically require a harness or connector repair.

  4. 04

    Failed display board

    Part replacement

    If the display board itself has failed, it cannot send or receive communication signals regardless of the condition of the main board or wiring. A persistent No Comm error after a power cycle and wiring inspection points toward this possibility.

  5. 05

    Failed main control board

    Part replacement

    A defective main control board may be unable to initiate or sustain communication with the display. This is typically diagnosed after ruling out wiring issues and confirming the display board is functional.

See the test procedure for each cause

Frequently asked questions about No Comm

What does No Comm mean on a U-Line refrigerator?
No Comm means the main control board and the display board have lost communication with each other. The two boards rely on a continuous data signal to coordinate refrigerator operation, and when that signal is interrupted, the unit displays this fault. It can result from something as simple as a power disruption or something more involved like a wiring fault or a failed board.
Will resetting the refrigerator clear the No Comm error?
A power reset is the first recommended step and will clear the error if it was caused by a temporary firmware lockup or power fluctuation. Disconnect the unit from power for one to two minutes, then restore power and check whether the error returns. If the No Comm fault comes back after resetting, a hardware issue with the wiring or one of the control boards is likely the cause.
How do I fix the No Comm error on a U-Line refrigerator?
Start by disconnecting power to the unit for at least one to two minutes and then reconnecting it. If the error clears, no further action is needed. If it persists, inspect the wiring harness between the main control board and the display for loose, damaged, or corroded connectors. If the wiring appears intact, contact U-Line Customer Care or a qualified technician to diagnose whether the display board or main control board needs replacement.
Is the No Comm error on a U-Line refrigerator a safety concern?
The No Comm error itself is not a direct safety hazard, but it does indicate that the control system is not operating normally. If the main board and display board cannot communicate, the refrigerator may not maintain accurate temperature control, which could affect food safety over time. Addressing the error promptly is advisable to ensure the unit is operating as intended.
How much does it cost to repair a No Comm error on a U-Line refrigerator?
If the issue is resolved by a power cycle, there is no cost involved. If a technician is needed, a service call typically runs in the range of $75 to $150 before any parts. Replacing a display board or main control board on a U-Line unit can add $150 to $400 or more depending on the specific model and part pricing. Getting a diagnostic assessment first will help clarify which component, if any, needs to be replaced.

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