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Error code reference

Samsung Air Conditioner Error Code 458

Over-voltage error detected in compressor current sensor

Samsung codesSamsung air conditioner codes

Over-voltage error detected in compressor current sensor - CT sensor value over 20A for 3 minutes or more.

First step from the service manual

Check if there is any problem with compressor; check electric leakage for compressor connecting wire.

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

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What 458 means on a Samsung air conditioner

Samsung air conditioner error code 458 indicates an over-voltage condition detected by the compressor current transformer (CT) sensor. Specifically, the CT sensor has measured a current value exceeding 20 amps for a continuous period of three minutes or more. The CT sensor monitors compressor current draw in real time, and when sustained high current is detected at this level, the system triggers error 458 to protect the compressor and associated electrical components from damage caused by overcurrent conditions.

The compressor is the most likely source of this fault. A failing compressor winding, seized compressor internals, or a compressor beginning to short internally can all cause sustained high current draw above the 20A threshold. Electrical leakage in the wiring connecting the compressor to the control board is another significant cause, as a partial ground fault in the compressor wiring can cause abnormally high current readings at the CT sensor even if the compressor itself is mechanically sound.

Diagnosis should begin with a physical inspection of the compressor and its connecting wires. Check for damaged wire insulation, signs of burning or arcing, and loose terminals at the compressor terminals. A clamp meter can be used to measure actual compressor current draw and confirm whether the CT sensor reading corresponds to real overcurrent. If wiring checks out, the compressor windings should be tested for resistance balance and insulation integrity to the chassis ground.

Source: manufacturer service documentation.

Common causes of 458

  1. 01

    Failing or seized compressor

    Part replacement

    A compressor with worn windings, internal shorts, or mechanical seizure will draw excessive current well above the 20A threshold. This is the most common root cause and can often be confirmed by measuring winding resistance and checking for ground faults at the compressor terminals.

  2. 02

    Electrical leakage in compressor wiring

    Part replacement

    Damaged or degraded insulation on the wires connecting the compressor to the inverter or control board can create a partial ground fault, causing the CT sensor to read abnormally high current. Inspect wiring for chafing, burns, or moisture intrusion.

  3. 03

    Low refrigerant charge

    Wiring / connection

    Insufficient refrigerant causes the compressor to work harder and run at elevated current levels for extended periods. This can push current readings above the 20A limit, triggering error 458.

  4. 04

    Faulty CT sensor

    Part replacement

    Although less common, the current transformer sensor itself can fail and report falsely elevated current values. If compressor winding tests and wiring inspections show no faults, the CT sensor should be evaluated as a potential cause.

  5. 05

    Supply voltage abnormality

    Wiring / connection

    Unstable or low supply voltage can cause the compressor to draw higher than normal current to maintain operation. Verify that incoming line voltage is within the required specification for the unit.

See the test procedure for each cause

Frequently asked questions about 458

What does 458 mean on a Samsung air conditioner?
Error 458 on a Samsung air conditioner means the compressor current sensor (CT sensor) has detected a current value exceeding 20 amps for three or more consecutive minutes. This is an over-current protection fault that causes the system to shut down to prevent compressor damage. The compressor itself or its connecting wiring is the primary area to inspect.
Can I fix Samsung error code 458 myself?
Some preliminary checks such as inspecting wiring for visible damage and verifying supply voltage can be done by a knowledgeable DIYer. However, testing compressor windings, checking for refrigerant charge, and replacing components like the compressor or CT sensor require specialized tools and, in the case of refrigerant work, EPA certification. It is strongly recommended to have a qualified technician handle this repair.
Is it safe to keep running my air conditioner with error 458 showing?
No. Error 458 indicates a serious electrical overcurrent condition involving the compressor. Running the unit while this fault is active risks further damage to the compressor, wiring, and control boards, and there is a potential electrical safety hazard if wiring insulation is compromised. The unit should remain off until the fault is diagnosed and corrected.
Will resetting the unit clear error 458?
A power reset may temporarily clear the error and allow the unit to restart, but if the underlying cause, such as a failing compressor or damaged wiring, has not been corrected, the error will return within minutes once current exceeds the 20A threshold again for the required duration. A reset should only be used as part of a diagnostic process, not as a fix.
How much does it cost to repair Samsung error code 458?
Repair costs depend heavily on the root cause. If the issue is wiring damage, repairs can range from around $100 to $300 including labor. A refrigerant recharge typically falls in the $150 to $400 range. If the compressor itself has failed, replacement is significantly more expensive, often ranging from $600 to $1,500 or more depending on the unit size and labor costs in your area.

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