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Error code reference

Thermador Refrigerator Error Code 5-1-1

Icemaker

Thermador codesThermador refrigerator codes

Icemaker: Main voltage is too high.

First step from the service manual

Check main voltage.

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

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What 5-1-1 means on a Thermador refrigerator

Error code 5-1-1 on a Thermador refrigerator indicates that the icemaker control system has detected main supply voltage that exceeds the acceptable operating range. The icemaker module continuously monitors the incoming voltage to ensure safe and reliable ice production. When voltage rises above the specified threshold, the system triggers this fault to prevent potential damage to the icemaker's electronic components and motor.

High voltage conditions can originate from the home's electrical supply, wiring issues within the refrigerator, or problems with the household circuit feeding the appliance. The icemaker relies on stable voltage to operate its water inlet valve, harvest motor, and control board correctly. Overvoltage can stress these components and, if left unaddressed, may cause premature failure of the icemaker assembly or its associated electronics.

The first and most critical diagnostic step is measuring the actual main supply voltage at the outlet or junction point serving the refrigerator. A properly calibrated multimeter should be used to confirm whether the voltage is genuinely out of range or whether a fault within the icemaker's sensing circuitry is producing a false reading. If supply voltage at the wall is within normal range (typically 120V AC for North American installations), the issue may lie within the icemaker control board or its voltage monitoring circuit rather than the external power supply.

Source: manufacturer service documentation.

Common causes of 5-1-1

  1. 01

    High household supply voltage

    Wiring / connection

    The voltage delivered by the utility to your home may be elevated above normal levels, which the icemaker control detects as an overvoltage condition. Measure voltage at the outlet with a multimeter to confirm whether it exceeds the normal range.

  2. 02

    Faulty icemaker control board

    Part replacement

    The icemaker's control board contains the voltage monitoring circuitry, and a defective board may misread normal voltage as too high, triggering a false 5-1-1 fault. If supply voltage measures within spec, the control board is the primary suspect.

  3. 03

    Wiring or connection issue within the refrigerator

    Wiring / connection

    Damaged, corroded, or loose wiring between the main board and the icemaker module can cause abnormal voltage readings at the icemaker's input. Inspect the wiring harness and connectors for signs of damage or poor contact.

  4. 04

    Electrical surge or transient event

    Wiring / connection

    A recent power surge, such as from a lightning strike or utility grid fluctuation, can temporarily spike voltage and trigger this fault code even if current supply voltage has returned to normal. Check for any reported outages or surge events prior to the fault appearing.

  5. 05

    Failing main refrigerator control board

    Part replacement

    If the main refrigerator control board is malfunctioning, it may supply or report incorrect voltage levels to the icemaker module, resulting in a 5-1-1 error. This is a less common cause but should be evaluated if all other components check out normal.

See the test procedure for each cause

Frequently asked questions about 5-1-1

What does 5-1-1 mean on a Thermador refrigerator?
Error code 5-1-1 on a Thermador refrigerator means the icemaker has detected that the main supply voltage is too high. The icemaker's control system monitors incoming voltage and shuts down ice production when voltage exceeds the acceptable range. This protects the icemaker's motor, water inlet valve, and electronic components from overvoltage damage. The first step is to measure the actual supply voltage at the outlet using a multimeter.
How do I fix error code 5-1-1 on my Thermador refrigerator?
Start by measuring the voltage at the wall outlet supplying the refrigerator to determine if the household supply voltage is genuinely elevated. If the voltage is normal, the problem likely lies with the icemaker control board or internal wiring, which may need inspection or replacement. If the supply voltage is high, contact your utility provider or an electrician to address the issue before running the appliance. Do not continue to operate the icemaker under confirmed overvoltage conditions, as this can damage components.
Is error code 5-1-1 on a Thermador refrigerator dangerous?
A genuine overvoltage condition feeding your refrigerator can pose risks to the appliance's electronics and, in severe cases, could contribute to overheating of components. Until the root cause is confirmed, it is advisable to keep the icemaker disabled. If supply voltage at the outlet is confirmed to be significantly elevated, avoid using the refrigerator until the electrical issue is corrected by a qualified electrician.
Will resetting the refrigerator clear error code 5-1-1?
Resetting the refrigerator by unplugging it for several minutes may temporarily clear the 5-1-1 fault code, but the error will return if the underlying voltage issue has not been resolved. A reset is only useful as a diagnostic step after the root cause has been identified and corrected. If the code reappears shortly after a reset, the overvoltage condition or the faulty sensing component is still present and requires further diagnosis.
How much does it cost to repair error code 5-1-1 on a Thermador refrigerator?
Repair costs vary depending on the root cause. If the issue is limited to an electrician correcting high household voltage, costs can range from around $75 to $200 or more for a service call. If the icemaker control board requires replacement, parts and labor combined typically range from $150 to $400 or higher depending on parts availability and local labor rates. A main refrigerator control board replacement would generally cost more, often in the $300 to $600 range including labor.

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