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Error code reference

Samsung Air Conditioner Error Code E307

PWM discharge temperature sensor error OPEN/SHORT

Samsung codesSamsung air conditioner codes

PWM discharge temperature sensor error OPEN/SHORT - 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 if sensor connector is separated from PCB; measure resistance.

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

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What E307 means on a Samsung air conditioner

Error code E307 on a Samsung air conditioner indicates a fault with the PWM (Pulse Width Modulation) discharge temperature sensor located in the outdoor unit. This sensor monitors the refrigerant discharge temperature, which is critical for protecting the compressor from overheating and ensuring efficient system operation. The error is triggered only when the outdoor ambient temperature is above -10°C, which prevents false faults during extremely cold conditions. The system flags an OPEN circuit condition when the sensor signal voltage rises above 4.95V, corresponding to a temperature reading below -30°C, and flags a SHORT circuit condition when the voltage drops below 0.5V, corresponding to a reading above 151°C. Neither of these readings reflects actual operating conditions, so the controller correctly identifies them as sensor failures.

The PWM discharge temperature sensor is a thermistor-type component mounted near the compressor discharge line in the outdoor unit. Its resistance changes with temperature, and the PCB converts that resistance into a voltage signal for interpretation. When the connector separates from the PCB or the sensor element itself fails, the signal either goes to the supply rail voltage (OPEN) or collapses toward ground (SHORT). Both fault states cause the outdoor unit to shut down to protect the compressor from operating without reliable temperature monitoring.

Diagnosis begins by inspecting the sensor connector at the outdoor PCB for a clean, fully seated connection. If the connector is secure, the next step is measuring the sensor resistance directly at the sensor leads and comparing the reading to the temperature-resistance curve specified for this sensor type. A reading of infinite resistance confirms an open circuit in the sensor or wiring, while a near-zero reading confirms a short. Damaged wiring between the sensor and the PCB, corrosion at the connector pins, and physical sensor failure are all common root causes.

Source: manufacturer service documentation.

Common causes of E307

  1. 01

    Disconnected sensor connector at outdoor PCB

    Wiring / connection

    Vibration from normal operation or rough handling during service can cause the sensor connector to back out of its socket on the outdoor PCB. Visually inspect the connector seating and press it firmly into place before further testing.

  2. 02

    Failed discharge temperature sensor (open circuit)

    Part replacement

    The thermistor element inside the sensor can fail open, causing the signal voltage to rise above 4.95V and triggering the OPEN fault. Measure resistance across the sensor leads; an infinite or extremely high reading confirms the sensor has failed.

  3. 03

    Shorted discharge temperature sensor

    Part replacement

    The sensor can internally short, collapsing the signal voltage below 0.5V and triggering the SHORT fault. A near-zero resistance reading across the sensor terminals confirms this failure mode.

  4. 04

    Damaged or pinched sensor wiring

    Part replacement

    The wiring harness between the sensor and the PCB can become pinched, chafed, or broken, causing either an open or short condition depending on the failure type. Inspect the full wire run for visible damage, kinking, or contact with sharp edges.

  5. 05

    Corrosion or contamination at connector pins

    Wiring / connection

    Moisture ingress into the outdoor unit can cause oxidation on the sensor connector pins, increasing resistance or creating intermittent contact that registers as a fault. Inspect pins for discoloration or buildup and clean or replace the connector as needed.

See the test procedure for each cause

Frequently asked questions about E307

What does E307 mean on a Samsung air conditioner?
E307 indicates a PWM discharge temperature sensor error in the outdoor unit. The control board has detected that the sensor signal voltage is either above 4.95V (indicating an open circuit, reading below -30°C) or below 0.5V (indicating a short circuit, reading above 151°C). Neither condition is a real temperature, so the system shuts down to protect the compressor. This fault only activates when outdoor ambient temperature is above -10°C.
Can I fix E307 myself or do I need a technician?
If the sensor connector has simply come loose from the outdoor PCB, a knowledgeable DIYer comfortable working inside an outdoor unit can reseat it and clear the fault. However, if the sensor or wiring needs to be replaced, or if resistance measurements are required to confirm the diagnosis, a qualified HVAC technician is the safer choice. Working inside the outdoor unit involves exposure to high-voltage components and refrigerant lines.
Is it safe to keep running my air conditioner with an E307 error?
No. The unit will typically shut itself down when E307 is active precisely because the discharge temperature sensor is what protects the compressor from overheating. Operating the system without a functioning discharge temperature sensor risks compressor damage, which is one of the most expensive repairs on an air conditioner. The unit should remain off until the sensor fault is resolved.
How much does it cost to repair an E307 error on a Samsung air conditioner?
If the fix is simply reseating a loose connector, there may be little cost beyond a service call fee, typically in the range of $75 to $150. Replacing the discharge temperature sensor itself is generally an inexpensive part, but with labor the total repair cost commonly falls between $100 and $300. If the outdoor PCB is also damaged, costs can increase significantly depending on the unit model.
Will resetting the air conditioner clear the E307 error code?
A power reset may temporarily clear the code from the display, but if the underlying sensor fault still exists, the error will return quickly once the unit attempts to operate and the outdoor temperature is above -10°C. A reset alone is not a fix. The sensor connector, sensor resistance, and wiring must be inspected and the root cause corrected before the unit will operate normally.

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