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Error code reference

Sub-Zero Refrigerator Error Code 15 C 01

AC Condenser Fan Relay stuck closed

Sub-Zero codesSub-Zero refrigerator codes

AC Condenser Fan Relay stuck closed - power (AC or DC) to compressor at all times.

First step from the service manual

Verify and replace control board.

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 C 01 means on a Sub-Zero refrigerator

Error code 15 C 01 on a Sub-Zero refrigerator indicates that the AC condenser fan relay on the control board is stuck in the closed position. When this relay fails closed, it continuously supplies power, either AC or DC, to the compressor circuit rather than cycling it on and off as commanded by the control logic. The condenser fan relay is a critical switching component on the main control board, responsible for coordinating compressor operation with the cooling cycle demands of the refrigerator.

A relay stuck closed means the contacts have welded together or the relay coil is holding the circuit energized regardless of the board's control signal. This condition forces the compressor to run without interruption, which can cause the refrigerator to over-cool, put excessive stress on the compressor, and prevent the system from responding to temperature setpoints. Because the relay is physically integrated into the control board circuitry, it is not a separately replaceable component in most cases.

The primary diagnostic step is to verify the fault condition by confirming the compressor is receiving power at all times, even when the control system should have the circuit open. Once confirmed, the control board must be replaced, as the failed relay is part of the board assembly. Continuing to run the refrigerator with this fault risks compressor damage from continuous uninterrupted operation and potential overcooling of stored food.

Source: manufacturer service documentation.

Common causes of 15 C 01

  1. 01

    Failed control board relay

    Part replacement

    The relay contacts on the main control board have welded closed due to electrical arcing or component wear, keeping the compressor circuit energized at all times. This is the primary cause and is confirmed when the compressor runs continuously regardless of temperature settings.

  2. 02

    Control board electrical damage

    Part replacement

    Power surges or voltage spikes can damage the relay driver circuit on the control board, causing the relay to lock in the closed state. Inspect the board for visible burn marks or damaged components near the relay.

  3. 03

    Control board firmware or logic fault

    Part replacement

    In rare cases, a software or logic error within the control board can cause it to continuously command the relay closed. A board replacement resolves both hardware and embedded firmware issues simultaneously.

  4. 04

    Wiring short in the compressor circuit

    Wiring / connection

    A short circuit in the wiring harness between the control board and the compressor could simulate a relay-closed condition. Inspect the wiring for damaged insulation or pinched conductors before replacing the board.

See the test procedure for each cause

Frequently asked questions about 15 C 01

What does 15 C 01 mean on a Sub-Zero refrigerator?
Error code 15 C 01 means the AC condenser fan relay on the control board is stuck in the closed position, which keeps power supplied to the compressor at all times. The compressor should cycle on and off based on temperature demands, but this fault prevents that from happening. The control board must be inspected and replaced to resolve the issue.
Can I fix error code 15 C 01 myself on a Sub-Zero refrigerator?
The primary fix for this error code is replacing the main control board, which involves working with AC and DC electrical circuits inside the refrigerator. While a knowledgeable DIYer may be able to replace the board, the diagnostic process requires verifying live voltage at the compressor circuit, which carries real shock risk. Most homeowners should have a qualified appliance technician perform this repair.
Is it safe to keep using my Sub-Zero refrigerator when error code 15 C 01 is active?
Continued operation with error code 15 C 01 active is not recommended. With the compressor running continuously, the refrigerator can over-cool food and beverages, and the compressor itself is at risk of damage from uninterrupted operation without its normal rest cycles. It is best to address the fault promptly to avoid secondary damage.
Will resetting my Sub-Zero refrigerator clear error code 15 C 01?
A simple power reset is unlikely to permanently clear error code 15 C 01 because the underlying cause is a hardware failure of the relay on the control board. The relay contacts are physically stuck closed and cannot be reset through a software command or power cycle. The fault will return as long as the faulty control board remains in place.
How much does it cost to repair a Sub-Zero refrigerator with error code 15 C 01?
Repair costs for error code 15 C 01 typically involve the price of a replacement control board plus labor. Control board parts for Sub-Zero refrigerators generally range from $200 to $600 or more depending on the model, and professional labor can add $100 to $300 depending on your location and the technician. Total repair costs commonly fall in the range of $300 to $900.

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