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Error code reference

Sub-Zero Refrigerator Error Code 15 2 01

Freezer Compressor Relay is stuck closed; power to compressor at all times.

Sub-Zero codesSub-Zero refrigerator codes

Freezer Compressor Relay is stuck closed; power to compressor at all times.

First step from the service manual

Verify, 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 2 01 means on a Sub-Zero refrigerator

Error code 15 2 01 on a Sub-Zero refrigerator indicates that the freezer compressor relay is stuck in the closed position, meaning the compressor is receiving continuous power rather than being cycled on and off by the control system. Under normal operation, the control board sends signals to the compressor relay to regulate run cycles based on temperature demands. When this relay welds shut or fails in the closed position, the compressor runs without interruption, bypassing the normal thermostatic and defrost cycle controls entirely.

A compressor running continuously without proper cycling can cause a range of secondary problems. The freezer section may over-cool, ice buildup can accelerate, and the compressor motor itself is at risk of overheating and premature failure due to the lack of rest periods designed into normal operation. The evaporator may also frost over completely if defrost cycles are effectively blocked, reducing airflow and cooling efficiency across both compartments.

The primary diagnostic focus for this code is the control board, which houses the relay circuit responsible for switching compressor power. The relay contacts can weld together due to electrical arcing, age-related degradation, or voltage spikes, and when this happens the board cannot interrupt power to the compressor regardless of the control signal. Because the relay is integrated into the control board assembly in these units, the standard diagnostic and repair path is to verify the board is the source of the fault and then replace it. External wiring or compressor issues should be ruled out before condemning the board.

Source: manufacturer service documentation.

Common causes of 15 2 01

  1. 01

    Failed relay on the control board

    Part replacement

    The relay contacts on the control board have welded together due to arcing or age, keeping the compressor circuit permanently closed. This is the most common cause and is confirmed by replacing the control board.

  2. 02

    Voltage spike or power surge damage

    Part replacement

    A power surge can cause the relay contacts to arc and fuse shut. Inspect the board for visible burn marks or discoloration around the relay area as a supporting indicator.

  3. 03

    Control board firmware or logic fault

    Part replacement

    In some cases a control board logic error can cause the relay output to remain active continuously. Verifying the board output signal against expected cycling behavior helps confirm this before replacement.

  4. 04

    Wiring short in the compressor circuit

    Wiring / connection

    A short circuit in the wiring harness between the board and the compressor could mimic a stuck relay condition. Inspect the harness for damaged insulation or pinched wires before replacing the board.

See the test procedure for each cause

Frequently asked questions about 15 2 01

What does 15 2 01 mean on a Sub-Zero refrigerator?
Error code 15 2 01 means the freezer compressor relay is stuck in the closed position, causing the compressor to receive power continuously. Normally, the control board cycles the compressor on and off based on temperature demands. When this relay fails closed, the compressor runs without interruption, which can lead to over-cooling, excessive frost buildup, and compressor wear. The control board is the primary component to inspect and replace to resolve this fault.
Can I fix error code 15 2 01 myself?
Diagnosing and replacing the control board on a Sub-Zero refrigerator requires familiarity with appliance electronics and proper safety precautions when working with live circuits. A knowledgeable DIYer can inspect wiring for obvious damage, but replacing the control board is generally the recommended repair path and involves handling sensitive electronics. If you are not comfortable working with appliance control boards, a qualified technician is the safer choice.
Is it safe to keep using my Sub-Zero refrigerator when error 15 2 01 is active?
Continued use with this error active is not recommended for extended periods. A compressor running without normal cycling is at risk of overheating and early failure, and the freezer compartment may over-cool or develop heavy frost buildup that reduces performance. Addressing the fault promptly will prevent further damage to the compressor and other related components.
How much does it cost to repair error code 15 2 01 on a Sub-Zero refrigerator?
Repair costs vary depending on labor rates in your area and the specific control board required for your model, but control board replacements on high-end refrigerators like Sub-Zero units typically range from several hundred to over a thousand dollars including parts and labor. Getting a diagnosis confirmed by a Sub-Zero certified technician before ordering parts is advisable to avoid unnecessary expense.
Will resetting my Sub-Zero refrigerator clear error code 15 2 01?
A reset is unlikely to permanently clear error 15 2 01 because the fault is caused by a physical relay failure on the control board, not a transient software glitch. Even if a reset temporarily clears the code, it will return as soon as the system detects the compressor running outside its normal cycle pattern. The underlying relay fault must be corrected by replacing the control board for the error to be resolved.

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