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Error code reference

Samsung Air Conditioner Error Code E422

SUMP TEMP FIXED 2 sensor OPEN/SHORT error. Detected when outdoor temp over -10°C. Error level

Samsung codesSamsung air conditioner codes

SUMP TEMP FIXED 2 sensor OPEN/SHORT error. Detected when outdoor temp over -10°C. Error level: Over 4.95V (-30°C), below 0.5V (151°C).

First step from the service manual

Check sensor connector; measure resistance across both terminals.

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

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What E422 means on a Samsung air conditioner

Error code E422 on a Samsung air conditioner indicates a fault with the Sump Temperature Fixed 2 sensor, detected as either an open circuit or a short circuit condition. This sensor monitors the sump temperature in the outdoor unit and plays a role in protecting the compressor and refrigerant circuit during low-ambient operating conditions. The controller only triggers this error when the outdoor ambient temperature is above -10 degrees Celsius, which rules out false positives caused by extreme cold affecting normal sensor resistance ranges. The fault thresholds are defined by voltage readings at the control board: a reading above 4.95 volts corresponds to approximately -30 degrees Celsius and indicates an open circuit, while a reading below 0.5 volts corresponds to approximately 151 degrees Celsius and indicates a short circuit.

When the sensor signal falls outside the valid voltage window under these ambient conditions, the control board interprets the reading as physically impossible and flags the error. Open circuit faults are most commonly caused by a broken sensor wire, a pulled or corroded connector, or complete sensor failure. Short circuit faults typically result from damaged wiring with insulation worn through, a sensor element that has failed with near-zero resistance, or moisture ingress into the connector causing a low-resistance path to ground. Both fault types prevent accurate sump temperature monitoring, which can lead to compressor damage if the system continues to operate without protection.

Diagnosing E422 begins at the sensor connector. With the power disconnected, the technician should inspect the connector for corrosion, bent pins, or physical damage, then measure resistance across the two sensor terminals. A properly functioning NTC thermistor will show a measurable resistance value that varies with temperature. An open circuit will read infinite resistance (OL on a digital multimeter), while a short will read near zero ohms. If the connector and wiring check out, the sensor itself should be replaced.

Source: manufacturer service documentation.

Common causes of E422

  1. 01

    Faulty or failed sump temperature sensor

    Part replacement

    The NTC thermistor element inside the sensor can fail over time, producing a resistance value that falls outside the valid range. This causes the control board to read a voltage above 4.95V or below 0.5V, triggering E422.

  2. 02

    Loose or disconnected sensor connector

    Wiring / connection

    Vibration from the compressor or outdoor fan can loosen the sensor connector over time, creating an open circuit. Inspect the connector at both the sensor end and the control board end for secure seating.

  3. 03

    Corroded or damaged connector pins

    Wiring / connection

    Moisture ingress into the outdoor unit can cause corrosion on the sensor connector pins, increasing contact resistance to the point where the circuit reads as open. Look for green or white oxidation on the terminals.

  4. 04

    Damaged sensor wiring

    Part replacement

    Rodent damage, pinching against sheet metal, or UV degradation can break or short the sensor wires. Trace the full length of the sensor harness and look for cut, frayed, or melted insulation.

  5. 05

    Control board input circuit fault

    Part replacement

    If the sensor and its wiring both test correctly, the input circuit on the outdoor unit control board may have failed, causing it to misread the sensor voltage. This is less common but should be considered after all other components are confirmed good.

See the test procedure for each cause

Frequently asked questions about E422

What does E422 mean on a Samsung air conditioner?
E422 indicates an open or short circuit fault on the Sump Temperature Fixed 2 sensor in the outdoor unit. The error is triggered when the outdoor temperature is above -10 degrees Celsius and the sensor voltage reads above 4.95V (open circuit) or below 0.5V (short circuit). These voltage thresholds correspond to temperature readings of approximately -30 degrees Celsius and 151 degrees Celsius, which the controller recognizes as physically implausible. The system halts normal operation to protect the compressor until the fault is resolved.
Can I fix the E422 error myself?
A homeowner with basic electrical knowledge can safely inspect the outdoor unit sensor connector for visible damage, corrosion, or loose connections with the power turned off. However, measuring sensor resistance and replacing components requires a multimeter and familiarity with refrigerant system components. If the wiring and connector look intact, it is best to have a qualified technician perform the resistance measurement and sensor replacement.
Will resetting the air conditioner clear the E422 error?
Resetting the unit by cycling power may temporarily clear the error display, but the fault will return quickly if the underlying sensor problem has not been fixed. The control board continuously monitors the sensor voltage during operation and will re-trigger E422 as soon as it detects an out-of-range reading. A permanent fix requires repairing or replacing the faulty sensor or wiring.
Is it safe to run my air conditioner with error code E422 active?
It is not recommended to continue operating the system with E422 active. The sump temperature sensor provides data that helps protect the compressor from damage during certain operating conditions. Running the unit without valid sensor input can lead to compressor overheating or other failures that are significantly more costly to repair than the sensor itself.
How much does it cost to repair a Samsung air conditioner E422 error?
If the issue is simply a loose connector, there may be no parts cost, though you will likely still pay a diagnostic service fee in the range of $75 to $150. Replacing the sump temperature sensor typically costs between $20 and $80 for the part, plus labor. If the wiring harness is damaged or the control board needs replacement, total repair costs can range from $150 to $400 or more depending on the unit and local labor rates.

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