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Error code reference

Samsung Air Conditioner Error Code E464

Compressor down by compressor discharge temperature sensor value exceeding 135°C.

Samsung codesSamsung air conditioner codes

Compressor down by compressor discharge temperature sensor value exceeding 135°C.

First step from the service manual

Check compressor discharge sensor resistance value; replace sensor if abnormal.

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

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What E464 means on a Samsung air conditioner

Samsung E464 is a compressor protection fault that triggers when the discharge temperature sensor reports a value exceeding 135°C at the compressor outlet. The discharge temperature sensor monitors the temperature of refrigerant gas leaving the compressor. When this reading climbs above the 135°C threshold, the system interprets the condition as a risk of compressor damage and shuts the compressor down to prevent failure. The unit will not resume normal operation until the fault condition is resolved and the system is properly cleared.

The root cause of E464 can be either a genuine overtemperature condition at the compressor or a faulty discharge temperature sensor providing an inaccurate reading. A genuine overtemperature event can result from low refrigerant charge, restricted airflow across the condenser, non-condensable gases in the refrigerant circuit, or a failing compressor that is working inefficiently and generating excess heat. A defective sensor, on the other hand, will report an out-of-range resistance value that does not correspond to actual refrigerant temperatures.

The first diagnostic step is to measure the resistance of the compressor discharge temperature sensor and compare it against the expected resistance-to-temperature curve for the sensor. If the resistance value is abnormal at ambient temperature, the sensor itself is the likely culprit and should be replaced before further diagnosis. If the sensor checks out as functional, the technician must investigate the refrigerant circuit, condenser airflow, and compressor health to identify the true source of the elevated discharge temperature.

Source: manufacturer service documentation.

Common causes of E464

  1. 01

    Faulty compressor discharge temperature sensor

    Part replacement

    The sensor itself may be defective and reporting a false high-temperature reading. Measuring the sensor's resistance value and finding it outside the expected range confirms this diagnosis.

  2. 02

    Low refrigerant charge

    Part replacement

    Insufficient refrigerant causes the compressor to work harder and compress less efficiently, driving up discharge temperatures to dangerous levels. A manifold gauge set will confirm low system pressure.

  3. 03

    Restricted or blocked condenser airflow

    Wiring / connection

    Dirt, debris, or vegetation blocking the outdoor condenser coil prevents proper heat rejection, causing refrigerant discharge temperatures to rise excessively. Inspect the coil and surrounding clearance for obstructions.

  4. 04

    Non-condensable gases in the refrigerant circuit

    Part replacement

    Air or moisture contaminating the refrigerant circuit raises condensing pressure and discharge temperature. This typically occurs after improper servicing where the system was not properly evacuated before recharging.

  5. 05

    Failing or worn compressor

    Part replacement

    A compressor with worn internal components may operate inefficiently, generating heat beyond what the refrigerant circuit can manage. If all other causes are ruled out and discharge temperatures are genuinely elevated, compressor condition should be evaluated.

See the test procedure for each cause

Frequently asked questions about E464

What does E464 mean on a Samsung air conditioner?
E464 indicates that the compressor discharge temperature sensor has reported a value exceeding 135°C, which is above the safe operating threshold. Samsung's system responds by shutting the compressor down to prevent damage. The fault can be caused by an actual overtemperature condition in the refrigerant circuit or by a defective sensor giving a false reading. A technician should check the sensor resistance first to determine whether the sensor or the refrigerant system is at fault.
Can I fix E464 myself without a technician?
Some basic checks are accessible to a knowledgeable DIYer, such as clearing debris from the outdoor condenser coil and verifying that airflow around the unit is not restricted. However, checking sensor resistance values, diagnosing refrigerant charge, and handling refrigerant requires certified technicians and proper equipment. If the sensor needs replacement or the refrigerant system is involved, professional service is necessary.
Is it safe to keep running my air conditioner when E464 is displayed?
No. The E464 fault shuts the compressor down specifically to protect it from heat damage, and the unit will not run normally while the fault is active. Attempting to force the system to operate without resolving the underlying cause risks permanent compressor failure, which is a significantly more expensive repair. The unit should remain off until the fault is properly diagnosed and corrected.
Will resetting the air conditioner clear the E464 error?
A power reset may temporarily clear the fault code and allow the unit to restart, but if the root cause is not resolved, the E464 error will return once the compressor discharge temperature sensor again reads above 135°C. Resetting without diagnosis is not a fix. If the sensor is faulty or a refrigerant issue exists, the fault will reappear and continued operation can cause compressor damage.
How much does it cost to repair a Samsung air conditioner showing E464?
Repair costs vary depending on the cause. Replacing a faulty discharge temperature sensor is typically the least expensive repair, generally ranging from around $100 to $250 including labor. Refrigerant recharge or leak repair can cost between $150 and $500 or more depending on the refrigerant type and leak location. Compressor replacement is the most costly outcome, often ranging from $700 to $1,800 or higher depending on unit size and model.

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