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Error code reference

Sub-Zero Refrigerator Error Code 15 1 00

Zone 1 compressor relay stuck open

Sub-Zero codesSub-Zero refrigerator codes

Zone 1 compressor relay stuck open. No current detected. No load, open relay, inverter, or harness.

First step from the service manual

Check wiring, compressor, inverter, and control board connections; possible issue with control board or inverter.

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

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  • 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
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What 15 1 00 means on a Sub-Zero refrigerator

Error code 15 1 00 on a Sub-Zero refrigerator indicates that the Zone 1 compressor relay is stuck in the open position. In this condition, the control system expects to detect current flowing through the compressor circuit when the relay closes, but no current is present. This points to a failure somewhere in the power path between the control board and the compressor itself, specifically within the relay circuit that governs Zone 1 cooling.

The fault can originate from several components. The relay itself may be mechanically or electrically failed in the open state, preventing the compressor from receiving a start signal. The inverter board, which drives the variable-speed compressor in Sub-Zero units, may be faulty and unable to energize the circuit. Wiring harness issues such as broken conductors, corroded terminals, or loose connectors along the compressor circuit can also interrupt current flow and trigger this code. In some cases, the compressor motor windings may be open, which would show no load on the circuit even if the relay closes properly.

Diagnosis should begin with a thorough inspection of all wiring and connector harnesses between the control board, inverter, and compressor. Verify that all connections are fully seated and free of corrosion or damage. If the wiring checks out, the inverter board and control board should be evaluated for proper output signals. The compressor itself should be tested for continuity across its motor windings to rule out an internal open-circuit failure. Replacing the faulty component, whether relay, inverter, harness, or compressor, will be required to clear the fault.

Source: manufacturer service documentation.

Common causes of 15 1 00

  1. 01

    Faulty inverter board

    Part replacement

    The inverter board controls and powers the compressor motor. If the inverter has failed internally, it cannot energize the relay circuit, resulting in no current detected at the compressor.

  2. 02

    Wiring harness damage or loose connections

    Wiring / connection

    Broken wires, corroded terminals, or unseated connectors between the control board, inverter, and compressor can interrupt current flow. Inspect all connectors in the Zone 1 compressor circuit for damage or poor contact.

  3. 03

    Stuck open or failed compressor relay

    Part replacement

    The relay responsible for closing the compressor circuit may be mechanically or electrically failed in the open position, preventing any current from reaching the compressor. This can often be identified by testing relay coil continuity and contact resistance.

  4. 04

    Open compressor motor windings

    Part replacement

    If the compressor motor has an internal open circuit, no load will be detected even when the relay closes and the inverter operates correctly. Testing continuity across the compressor terminals will confirm this condition.

  5. 05

    Control board malfunction

    Part replacement

    The main control board may fail to send the correct signal to close the relay or communicate with the inverter. This is typically diagnosed after the wiring, inverter, and compressor have been ruled out.

See the test procedure for each cause

Frequently asked questions about 15 1 00

What does 15 1 00 mean on a Sub-Zero refrigerator?
Error code 15 1 00 means the Zone 1 compressor relay is stuck open and no current is being detected in the compressor circuit. The refrigerator's control system expected to see a load when the relay closed, but found none. This indicates a problem with the relay itself, the inverter board, the wiring harness, or the compressor. A technician should inspect all components in this circuit to identify the specific failure point.
Can I fix error code 15 1 00 myself?
Some basic checks, such as inspecting wiring connections and ensuring all harness connectors are fully seated, can be done by a knowledgeable homeowner. However, testing the inverter board, relay, and compressor windings requires electrical diagnostic tools and familiarity with refrigeration systems. Most repairs associated with this code, including component replacement, are best handled by a qualified appliance technician.
Is it safe to keep using my refrigerator when code 15 1 00 is active?
If the Zone 1 compressor is not running due to this fault, the refrigerator will not maintain safe food storage temperatures in that zone. Continuing to store perishable food in an affected compartment could lead to spoilage. It is recommended to address the fault promptly and transfer perishables to another refrigerator if cooling is insufficient.
How much does it cost to repair error code 15 1 00 on a Sub-Zero refrigerator?
Repair costs vary depending on which component has failed. Wiring repairs may cost relatively little in parts but require labor time for diagnosis. An inverter board replacement typically falls in the range of several hundred dollars in parts plus labor. Compressor replacement is the most expensive scenario, often ranging from several hundred to over a thousand dollars depending on the model. Getting a diagnostic visit from a Sub-Zero authorized technician will provide an accurate estimate.
Will resetting the refrigerator clear error code 15 1 00?
A power reset may temporarily clear the error code from the display, but if the underlying fault in the compressor relay circuit is still present, the code will return once the control system runs its diagnostics again. Resetting the unit does not repair failed components such as a faulty inverter, open relay, or damaged wiring. A proper repair addressing the root cause is required to permanently resolve the fault.

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