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Error code reference

Viking Ice Maker Error Code 4 blinks

Both bin and evaporator sensors are open or shorted.

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Both bin and evaporator sensors are open or shorted.

First step from the service manual

Test both bin and evaporator thermistors for resistance and compare to Resistance versus Temperature Chart. Replace any thermistor that is out of specification.

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

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What 4 blinks means on a Viking ice maker

The 4-blink error code on a Viking ice maker indicates that the control board has detected a fault in both the bin thermistor and the evaporator thermistor simultaneously. These two sensors are negative temperature coefficient (NTC) thermistors, meaning their electrical resistance decreases as temperature increases. The control board continuously monitors the resistance values of both sensors and compares them to a known resistance versus temperature chart. When both sensors fall outside the expected resistance range, either reading as an open circuit (infinite resistance) or a short circuit (near-zero resistance), the board triggers this combined fault code.

The bin thermistor monitors ice level and prevents the bin from overfilling, while the evaporator thermistor tracks the temperature of the evaporator plate to control the freeze and harvest cycles. When both sensors fail simultaneously or read out of spec at the same time, the ice maker cannot safely manage either function, so it halts operation and alerts with the 4-blink sequence. A simultaneous fault in two separate sensors often points to a shared wiring harness issue, a connector problem, or a power supply fault affecting the sensor circuit rather than two independent sensor failures.

Diagnosis begins with disconnecting the thermistors and measuring their resistance with a multimeter, then comparing those readings to the resistance versus temperature chart specific to the unit. If a thermistor reads open or shorted at a known ambient temperature, it has failed and requires replacement. If both sensors test within spec on the bench but the code persists, inspect the wiring harness and connector terminals between the sensors and the control board for corrosion, damage, or poor contact.

Source: manufacturer service documentation.

Common causes of 4 blinks

  1. 01

    Damaged or corroded wiring harness connector

    Part replacement

    A shared connector or harness section serving both thermistors can corrode, crack, or develop a loose pin, causing both sensors to read incorrectly at the control board. Inspect the connector body and terminal pins for moisture damage, oxidation, or pushed-back terminals.

  2. 02

    Failed bin thermistor

    Part replacement

    The bin thermistor can fail open or short due to moisture exposure or physical damage, producing a reading outside the resistance versus temperature curve. Test resistance at a known temperature and compare to the chart to confirm the fault.

  3. 03

    Failed evaporator thermistor

    Part replacement

    The evaporator thermistor is subject to repeated freeze and thaw cycles which can degrade the sensor element or its insulation over time, causing an open or shorted condition. Resistance testing will confirm whether this sensor is out of specification.

  4. 04

    Broken or shorted wiring between sensors and control board

    Part replacement

    Chafed, pinched, or broken wires in the harness routing from either thermistor to the control board can cause open-circuit or short-circuit readings. Visually inspect the full wire run and test continuity on each conductor.

  5. 05

    Faulty control board

    Part replacement

    If both thermistors and all associated wiring test within specification, the control board itself may have a failed input circuit that is misreading both sensor signals. This is the least common cause and should only be considered after all sensors and wiring are confirmed good.

See the test procedure for each cause

Frequently asked questions about 4 blinks

What does 4 blinks mean on a Viking ice maker?
The 4-blink code means the control board has detected that both the bin thermistor and the evaporator thermistor are either open-circuited or short-circuited. Both sensors are outside the acceptable resistance range for the current temperature conditions. The ice maker shuts down because it cannot safely manage the freeze or harvest cycles without reliable temperature data from both sensors.
Can I fix the 4-blink error on my Viking ice maker myself?
A knowledgeable DIYer with a multimeter can perform the core diagnostic step, which involves disconnecting each thermistor and testing its resistance, then comparing the reading to the resistance versus temperature chart. If a thermistor is confirmed faulty, replacing it is straightforward. However, if the wiring harness or control board is involved, the repair becomes more complex and may be better handled by a certified technician.
Will resetting the Viking ice maker clear the 4-blink error code?
A power cycle or reset may temporarily clear the error display, but the code will return as soon as the control board re-checks the thermistor circuits and finds them out of specification. The underlying fault in one or both sensors, or in the wiring connecting them, must be repaired before the error will stay cleared and the unit will resume normal operation.
Is it safe to use the ice maker while it shows the 4-blink error?
The ice maker will not produce ice while this fault is active because the control board halts operation when both temperature sensors are unreadable. There is no immediate safety hazard from the error itself, but you should not attempt to bypass the fault or force the unit to run without functional sensors, as the machine relies on those readings to prevent damage to the evaporator and compressor components.
How much does it cost to repair the 4-blink error on a Viking ice maker?
Repair costs vary depending on the root cause. Replacing one or both thermistors typically ranges from around $50 to $150 in parts, plus labor if a technician is involved. If the wiring harness needs repair or replacement the cost can increase to the $150 to $350 range. A control board replacement, if that is the confirmed cause, is the most expensive outcome and can range from $300 to $600 or more including labor.

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